This thesis investigates aspects of the ecology, morphology, bioacoustics, genetic relatedness, biogeography and taxonomy of cicadas in the Pauropsalta annulata Goding and Froggatt species complex, across their entire eastern Australian geographical distribution. These cicadas seem to emerge at the same sites annually, although the exact duration of their life cycle is not known. They are wary and mobile insects, with individuals generally taking flight at the first sign of disturbance, which makes them challenging to record, capture and observe. The males produce distinctive calling songs that have a consistent rhythmic structure, which is critically important for attracting females. In most cases, the songs are biphasic, with a penetrating introductory or "buzzing" component that apparently functions in mate attraction and a strongly structured cueing or "lilting" component for mate localisation. Initially Pauropsalta annulata was thought to comprise a single species with some degree of geographically structured variation in its calling song. Consequently, various "song types" had been recognised, but their precise relationship to one another had never been investigated. Therefore the structure of their calling songs were compared statistically across individuals of three song types, and this revealed four discrete clusters that were demonstrated to be independent of one another and consistent in their calling song structure. Plotting the geographical distributions of these cicadas revealed that each of the P. annulata song types is independently distributed geographically, with areas of overlap that are relatively small. Calling song structure is consistent for each song type across extensive geographical space and this structure holds even into areas of sympatry. One song type showed consistent differences from the others in male genitalia structure, and female ovipositor length differs significantly among three of the other song types. Each song type was found to be strongly associated with a small number of tree species and these associations are maintained into areas of sympatry. The spatial ecological and morphological comparisons in song structure, plant associations and morphology made in this study demonstrate that the P. annulata song types actually represent a complex of cryptic species. Two of the song types appear to intergrade in areas of sympatric overlap in terms of calling songs, plant associations and morphology, and thus represent subspecies as defined in population genetics terms. The components of the male calling song were then investigated to determine their specific functions and thus how they could delimit species boundaries. Significant differences were found in dominant song frequency between three of the four species, and may contribute to differential mate attraction. Both components of the song of each species have the same dominant frequency. Consistent differences were also evident, among species and subspecies, in the rhythmic structure of the "lilting" component of the male calling song. This component contains repeated phrases and each one of these provides a cue to which the conspecific female may respond. Her response is timed for the brief silent interval between the phrases. At this point the calling song becomes a duet, which enables the male to locate the female, as he actively searches for her on the surrounding branches at this stage. The calling song is discussed in terms of random mating within gene pools of these cicadas and in terms of its role as part of their broader fertilisation mechanism. A molecular analysis of the P. annulata species complex was performed to examine the phylogenetic relationships across 12 species and four subspecies defined in this study, and estimate divergence times within the group. Individual specimens were sampled widely across the geographical distributions of the species and subspecies where possible to account for genetic variation across space. DNA sequences from two loci were amplified: mitochondrial CO1 ("barcoding region") and a large intron from the dynamin nuclear gene. Separate phylogenies were reconstructed for each locus using maximum parsimony procedures and Bayesian posterior sampling with implementation of a relaxed molecular clock. The phylogenies from both genes provided strong support for the monophyly of the P. annulata species complex, and nine of the species were monophyletic based on the CO1 gene. The remaining three emerged non-monophyletic. Based on a clock calibration of 0.0165s/s/myr, the monophyletic clades represented by extant P. annulata species diverged about 4.5-8.0 million years ago. Those species that emerged non-monophyletic had shallower divergences, with the exception of one species, which exhibited haplotype diversity that conferred up to 13.2% sequence divergence between allopatric populations in CO1. Dynamin produced a broadly similar phylogenetic pattern to that of CO1, but the relationships among individuals across the species and subspecies that emerged non-monophyletic differed substantially. This lack of congruence between the two genomes, in combination with the dominance of internal haplotypes in both loci, indicates an overall pattern of deep coalescence rather than interspecific hybridization. Therefore the molecular data do not provide an alternative definition of species limits in the P. annulata species complex, despite some emerging non-monophyletic in this analysis. Sound interpretation of the phylogenetic pattern discovered here would not have been possible without the acoustic, ecological and geographical investigations on species limits that preceded this work. To determine what biological and climatic factors influence the present day distributions of these cicadas, the distributions of two of the most closely related species in the P. annulata species complex were compared with the distributions of the tree species with which each is mainly associated. Because a large part of their life cycle is subterranean, soil texture, pH, electrical conductivity and force required for surface penetration were compared across sites where each of the cicadas occur in sympatry and allopatry. Finally, the influence of temperature and rainfall variables were investigated by testing 'predicted distribution' models (formed using positive distribution records) against negative records for both sets of variables, individually and in combination. The results show that the extent of the distribution of the cicada species is substantially less than that of the associated tree species. The geographical distributions of one of the species may be influenced more by rainfall, or a combination of temperature and rainfall, whereas the other species appears to be more influenced by temperature alone. Both species tolerate soils with a wide range of pH levels, electrical conductivity and forces required for surface penetration. They both showed a strong association with soils that had a silt loam texture, with only few records from sandy soils. However, none of the soils sampled where the cicadas occurred were heavy clays, which suggests that the physical properties of such soils may provide an unsuitable environment for the nymphal stages of the life cycle of these particular cicadas. The resolution of species limits within the P. annulata species complex allowed the redescription of Pauropsalta annulata Goding and Froggatt sensu stricto and the description of 11 new species belonging to the P. annulata species group, all from eastern Australia. Two of these species comprise two subspecies each, also all new. New distribution records and calling song data are documented for the allied species, P. ayrensis Ewart, which is redescribed to include the characters newly recognised in the present study as significant taxonomically with respect to Pauropsalta cicadas. The treatment includes comprehensive descriptions of the morphology and calling songs of the species and subspecies, and separate descriptive keys are provided for both sets of characters. The new taxa comprise P. artatus sp. nov., P. corymbiae sp. nov., P. decorus sp. nov., P. graniticus sp. nov., P. inversus inversus subsp. nov., P. i. laboris subsp. nov., P. notialis notialis subsp. nov., P. notialis incitatus subsp. nov., P. simplex sp. nov., P. subtropicus sp. nov, P. torrensis sp. nov. and P. tremulus sp. nov. Areas of hybridization between P. n. notialis subsp. nov. and P. n. incitatus subsp. nov. are also documented, together with their calling songs and morphology, which justifies their subspecific status. The P. inversus subspecies are allopatric, but consistently differ in the duration between phrases of the calling song. Finally, the results and conclusions are amalgamated into a critical reassessment of what defines species limits and the most appropriate approaches to investigating species limits in sexual organisms. Some historical discussions are revisited, such as the question of the reality of species and how species are perceived under the premises of neoDarwinism. The realism of species demands that species limits are most realistically defined in terms of their fertilisation mechanism, for this delimits the gene pool and thus the distribution of adaptations (the calling song of cicadas, for example).

This thesis investigates aspects of the ecology, morphology, bioacoustics, genetic relatedness, biogeography and taxonomy of cicadas in the Pauropsalta annulata Goding and Froggatt species complex, across their entire eastern Australian geographical distribution. These cicadas seem to emerge at the same sites annually, although the exact duration of their life cycle is not known. They are wary and mobile insects, with individuals generally taking flight at the first sign of disturbance, which makes them challenging to record, capture and observe. The males produce distinctive calling songs that have a consistent rhythmic structure, which is critically important for attracting females. In most cases, the songs are biphasic, with a penetrating introductory or "buzzing" component that apparently functions in mate attraction and a strongly structured cueing or "lilting" component for mate localisation. Initially Pauropsalta annulata was thought to comprise a single species with some degree of geographically structured variation in its calling song. Consequently, various "song types" had been recognised, but their precise relationship to one another had never been investigated. Therefore the structure of their calling songs were compared statistically across individuals of three song types, and this revealed four discrete clusters that were demonstrated to be independent of one another and consistent in their calling song structure. Plotting the geographical distributions of these cicadas revealed that each of the P. annulata song types is independently distributed geographically, with areas of overlap that are relatively small. Calling song structure is consistent for each song type across extensive geographical space and this structure holds even into areas of sympatry. One song type showed consistent differences from the others in male genitalia structure, and female ovipositor length differs significantly among three of the other song types. Each song type was found to be strongly associated with a small number of tree species and these associations are maintained into areas of sympatry. The spatial ecological and morphological comparisons in song structure, plant associations and morphology made in this study demonstrate that the P. annulata song types actually represent a complex of cryptic species. Two of the song types appear to intergrade in areas of sympatric overlap in terms of calling songs, plant associations and morphology, and thus represent subspecies as defined in population genetics terms. The components of the male calling song were then investigated to determine their specific functions and thus how they could delimit species boundaries. Significant differences were found in dominant song frequency between three of the four species, and may contribute to differential mate attraction. Both components of the song of each species have the same dominant frequency. Consistent differences were also evident, among species and subspecies, in the rhythmic structure of the "lilting" component of the male calling song. This component contains repeated phrases and each one of these provides a cue to which the conspecific female may respond. Her response is timed for the brief silent interval between the phrases. At this point the calling song becomes a duet, which enables the male to locate the female, as he actively searches for her on the surrounding branches at this stage. The calling song is discussed in terms of random mating within gene pools of these cicadas and in terms of its role as part of their broader fertilisation mechanism. A molecular analysis of the P. annulata species complex was performed to examine the phylogenetic relationships across 12 species and four subspecies defined in this study, and estimate divergence times within the group. Individual specimens were sampled widely across the geographical distributions of the species and subspecies where possible to account for genetic variation across space. DNA sequences from two loci were amplified: mitochondrial CO1 ("barcoding region") and a large intron from the dynamin nuclear gene. Separate phylogenies were reconstructed for each locus using maximum parsimony procedures and Bayesian posterior sampling with implementation of a relaxed molecular clock. The phylogenies from both genes provided strong support for the monophyly of the P. annulata species complex, and nine of the species were monophyletic based on the CO1 gene. The remaining three emerged non-monophyletic. Based on a clock calibration of 0.0165s/s/myr, the monophyletic clades represented by extant P. annulata species diverged about 4.5-8.0 million years ago. Those species that emerged non-monophyletic had shallower divergences, with the exception of one species, which exhibited haplotype diversity that conferred up to 13.2% sequence divergence between allopatric populations in CO1. Dynamin produced a broadly similar phylogenetic pattern to that of CO1, but the relationships among individuals across the species and subspecies that emerged non-monophyletic differed substantially. This lack of congruence between the two genomes, in combination with the dominance of internal haplotypes in both loci, indicates an overall pattern of deep coalescence rather than interspecific hybridization. Therefore the molecular data do not provide an alternative definition of species limits in the P. annulata species complex, despite some emerging non-monophyletic in this analysis. Sound interpretation of the phylogenetic pattern discovered here would not have been possible without the acoustic, ecological and geographical investigations on species limits that preceded this work. To determine what biological and climatic factors influence the present day distributions of these cicadas, the distributions of two of the most closely related species in the P. annulata species complex were compared with the distributions of the tree species with which each is mainly associated. Because a large part of their life cycle is subterranean, soil texture, pH, electrical conductivity and force required for surface penetration were compared across sites where each of the cicadas occur in sympatry and allopatry. Finally, the influence of temperature and rainfall variables were investigated by testing 'predicted distribution' models (formed using positive distribution records) against negative records for both sets of variables, individually and in combination. The results show that the extent of the distribution of the cicada species is substantially less than that of the associated tree species. The geographical distributions of one of the species may be influenced more by rainfall, or a combination of temperature and rainfall, whereas the other species appears to be more influenced by temperature alone. Both species tolerate soils with a wide range of pH levels, electrical conductivity and forces required for surface penetration. They both showed a strong association with soils that had a silt loam texture, with only few records from sandy soils. However, none of the soils sampled where the cicadas occurred were heavy clays, which suggests that the physical properties of such soils may provide an unsuitable environment for the nymphal stages of the life cycle of these particular cicadas. The resolution of species limits within the P. annulata species complex allowed the redescription of Pauropsalta annulata Goding and Froggatt sensu stricto and the description of 11 new species belonging to the P. annulata species group, all from eastern Australia. Two of these species comprise two subspecies each, also all new. New distribution records and calling song data are documented for the allied species, P. ayrensis Ewart, which is redescribed to include the characters newly recognised in the present study as significant taxonomically with respect to Pauropsalta cicadas. The treatment includes comprehensive descriptions of the morphology and calling songs of the species and subspecies, and separate descriptive keys are provided for both sets of characters. The new taxa comprise P. artatus sp. nov., P. corymbiae sp. nov., P. decorus sp. nov., P. graniticus sp. nov., P. inversus inversus subsp. nov., P. i. laboris subsp. nov., P. notialis notialis subsp. nov., P. notialis incitatus subsp. nov., P. simplex sp. nov., P. subtropicus sp. nov, P. torrensis sp. nov. and P. tremulus sp. nov. Areas of hybridization between P. n. notialis subsp. nov. and P. n. incitatus subsp. nov. are also documented, together with their calling songs and morphology, which justifies their subspecific status. The P. inversus subspecies are allopatric, but consistently differ in the duration between phrases of the calling song. Finally, the results and conclusions are amalgamated into a critical reassessment of what defines species limits and the most appropriate approaches to investigating species limits in sexual organisms. Some historical discussions are revisited, such as the question of the reality of species and how species are perceived under the premises of neoDarwinism. The realism of species demands that species limits are most realistically defined in terms of their fertilisation mechanism, for this delimits the gene pool and thus the distribution of adaptations (the calling song of cicadas, for example).

The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a major pest of horticulture in eastern Australia, is a relatively poor coloniser of new habitat. This thesis examines behavioural properties that might limit the ability of B. tryoni to establish new populations. As the potential for B. tryoni to establish an outbreak population may be most directly limited by mechanisms associated with dispersal and mating behaviour, these two factors were the focus of this research project. The relevance of dispersal and mating behaviour for control of outbreak populations was assessed. Dispersal (i) Dispersal patterns of males and females are not different. Dispersal of post-teneral male B. tryoni from a point within an orchard near Richmond, New South Wales, was monitored following temporally replicated releases. Application of sterile insect technique (SIT) requires knowledge of dispersal from a release point so that effective release rates can be determined. In addition, dispersal following introduction to new habitat can lead to low or negative population growth and an Allee effect. In Spring and Autumn, 2001 � 2003, three different strains of B. tryoni were released: (1) wild flies reared from infested fruit collected in the Sydney Basin; (2) a laboratory-reared strain with a colour mutation (white marks); and (3) sterile flies obtained by gamma-irradiation of a mass-reared strain. Dispersal was monitored using a grid of traps baited with the male attractant, cuelure. During the majority of releases, flies were massmarked using a self-marking technique and fluorescent pigment powder to enable identification of recaptured flies. A preliminary study found that fluorescent pigment marks had no effect on adult survival and marks did not fade significantly in the laboratory over a period of five weeks after eclosion. As cuelure repels inseminated sexually mature female B. tryoni, unbaited, coloured flat sticky traps, and black and yellow sticky sphere traps baited with a food lure (protein autolysate solution) were used to supplement traps baited with cuelure. The effectiveness of these two sticky trap types was assessed, and recaptures used to compare patterns of dispersal from a release point by male and female B. tryoni. Fluorescent yellow (chartreuse), green, and clear unbaited flat sticky traps were relatively ineffective for monitoring dispersal of sterile male and female B. tryoni, recapturing only 0.1% of released sterile flies. Monitoring dispersal with sticky ball traps baited with protein autolysate solution was more successful, with yellow spheres and black spheres recapturing 1.7% and 1.5%, respectively. Trap colour had no effect on recaptures on flat sticky traps or sticky spheres. Equal recapture rates on yellow and black sticky sphere traps suggests that the odour of yeast autolysate solution was more important than colour for attraction of post-teneral flies to traps. Using the results of recaptures on odoriferous black and yellow sticky sphere traps within one week of release, regression equations of male and female recaptures per trap were found to be similar (Figure 4-3). This is the first study to clearly indicate that post-teneral dispersal patterns of male and female B. tryoni released from a point do not differ, enabling the use of existing models to predict density of both sexes of B. tryoni following post-teneral dispersal. (ii) Males disperse further in Spring than in Autumn, but this is not temperature-related. Analysis of replicated recaptures in traps baited with cuelure revealed that dispersal of male B. tryoni in an orchard near Richmond, New South Wales, was higher in Spring than in Autumn (Figure 5-6). As the maximum daily temperature was significantly higher in Spring than in Autumn this result was unexpected, since earlier studies have found that B. tryoni disperse at the onset of cool weather in search of sheltered over-wintering sites. Dispersal of post-teneral B. tryoni may have been affected by habitat suitability; it was found that seasonal trends in dispersal could have been influenced by local habitat variables. Low mean dispersal distances in Autumn may be explained by the presence of fruiting hosts in the orchard, or the availability of resources required by over-wintering flies. There was no significant correlation between temperature and mean dispersal distance, suggesting that higher rates of dispersal cannot be explained by temperature-related increases in activity. Recapture rate per trap was significantly negatively correlated with increasing daily maximum and average temperature. This may have consequences for detection of B. tryoni outbreaks in quarantine areas due to reduced cuelure trap efficiency. (iii) Maturity and source variation affect dispersal and response to cuelure. This research indicated that most male and female B. tryoni do not disperse far from a release point, suggesting that an invading propagule would not spread far in the first generation. However, there is considerable variation in flight capability among individuals. Comparison of wild, laboratory-reared white marks, and gamma-irradiated sterile male B. tryoni indicated that mean dispersal distance and redistribution patterns were not significantly affected by fly origin. Despite no difference in dispersal distance from the release point, recaptures of wild and sterile males per Lynfield trap baited with cuelure were highest within one week after release, whereas recaptures of white marks males per trap increased in the second week. This result may offer evidence to support the hypothesis that sterile male B. tryoni respond to cuelure at an earlier age. Rearing conditions used to produce large quantities of males for sterilisation by gamma-irradiation may select for earlier sexual maturity. Mating Behaviour (i) Density and sex ratio do not affect mating, except at low densities. Demographic stochasticity in the form of sex ratio fluctuations at low population density can lead to an observed Allee effect. The effect of local group density and sex ratio on mating behaviour and male mating success of a laboratory-adapted strain of B. tryoni was examined in laboratory cages. In the laboratory-adapted strain of B. tryoni used in this study, a group of one female and one male was sufficient for a good chance of mating success. The proportion of females mated and male mating success was not significantly affected by density or sex ratio, although variability in male mating success was higher at low density. This could indicate that mating success of B. tryoni can be reduced when local group density is low owing to decreased frequency in encounters between males and females. (ii) Mass-reared males exhibit aberrant mating behaviour, but this does not reduce mating success. Strong artificial selection in mass-rearing facilities may lead to decreased competitiveness of sterile males released in SIT programs as a result of alteration or loss of ecological and behavioural traits required in the field. The effects of domestication and irradiation on the mating behaviour of males of B. tryoni were investigated by caging wild, mass-reared and sterile (mass-reared and gammairradiated) males with wild females. Mating behaviour of mass-reared males was different from that of wild males, but behaviour of wild and sterile males was similar. Mass-reared males were found to engage in mounting of other males much more frequently than wild and sterile males, and began calling significantly earlier before darkness. Male calling did not appear to be associated with female choice of mating partners, although this does not exclude the possibility that calling is a cue used by females to discriminate between mating partners. Conditions used to domesticate and rear large quantities of B. tryoni for SIT may select for an alternative male mating strategy, with mass-reared males calling earlier and exercising less discrimination between potential mating partners. Despite differences in behaviour of wild, mass-reared and sterile males, frequency of successful copulations and mating success were similar. (iii) Pheromone-calling by males was increased in larger aggregations but this did not result in significantly more female visits. Finally, large laboratory cages with artificial leks were used to investigate the importance in B. tryoni of male group size for female visitation at lek sites and initiation of male pheromone-calling. Calling propensity of male B. tryoni was increased by the presence of conspecific males. Females visited the largest lek more frequently than single males, but there was no correlation between lek size and female visitation. Female B. tryoni had a limited capacity to perceive a difference between the number of calling males; female visitation at leks was only weakly associated with male calling, suggesting that lek size and the number of pheromone-calling males may not be the only factor important in locating mates in B. tryoni. The weak, but positive correlation between male calling and female visitation may indicate that passive attraction maintains lek-mating in B. tryoni. Further studies are essential on mating behaviour of B. tryoni, including identification of male mating aggregations in the field, measurement of habitat variables associated with male aggregations, the influence of density on wild B. tryoni mating success, and the role of pheromone-calling, in order to optimise use of SIT for control of this pest.

No description available.

<p>Diss. (sammanfattning) Umeå : Umeå universitet, 1992, härtill 8 uppsatser</p> / digitalisering@umu

The freshwater prawn, Macrobrachium rosenbergii (de Man, 1879) is an important aquaculture species but one that has the disadvantage of heterogeneous individual growth (HIG) according to different morphotypes. Chemical cues, especially, pheromones, are one of the most important communication types between individual prawns, along with visual and tactile methods. Testing pheromones, whilst restricting other cues, may therefore lead to a better understanding of the influence of these communicatory compounds on the prawn reproductive process. The three principle objectives of this study were therefore: 1) To examine the effect of moult stage and morphotype on pheromone-induced sexual behaviour 2) To examine the role of pheromone / urine concentrations on sexual attraction behaviour 3) To describe the functional morphology of the antennal gland and examine its possible role in pheromone production and release. Identical bioassay tanks were designed and constructed to study the reproductive behaviour of prawns. Experiments were set up to examine responses to pheromone release by live prawns over 30 minutes and behavioural response observations were made with the aid of a Closed-Circuit Videotape System (CCVS). Results were statistically analysed using a repeated measures general linear model (GLM). Three trials were designed to test the effect of moult stage of both males and females and male morphotypes on sexual attraction behavioural responses. Twelve prawns were used for each trial and each prawn was used five times (1 no-pheromone control and 4 for experimental tests). The first trial studied the effect of female moult stages (pre-, inter and newly-moulted) on sexual attraction behaviour of blue claw (BC) male. Results of this trial showed that newly-moulted females spent significantly (p<0.05) less time approaching the BC male than the pre- and inter-moult females. The second trial studied the effect of male moult stage (pre-, inter and newly-moulted) on sexual attraction to receptive females. Results showed that the time taken by the inter-moult males was (p<0.05) less than the pre- and newly-moulted males in approaching the newly-moulted female. The third trial tested the effect of male morphotypes (small male, SM, orange claw, OC and dominant blue claw, BC) on sexual attraction behaviour towards newly-moulted females. Results showed that the BC male was significantly more attractive (p<0.05) than other morphotypes to newly-moulted females and that the OC male was the least attractive. The role of moulting stage for both male and female prawns on reproductive response behaviour was investigated. Because BC males responded significantly faster towards newly-moulted female more than to either pre-or inter-moult females, results of the first trial suggest that BC males are able to use different chemical cues to gather information about a conspecific’s gender and can differentiate female’s moult stages. Since BC males responded significantly faster towards newly-moulted females more than to either pre-or inter-moult females, this suggests that females at this particular stage released a distinct sexual pheromone or concentration of pheromone that differed from those pheromones released by both pre- and inter-moult females. In contrast, newly-moulted females prefer the inter-moult BC males which indicate that females have an ability to distinguish the moult status of BC males. Furthermore, it indicates that pheromone characteristics change with the moult status of BC males. Also, newly-moulted females are most likely to be avoiding the potential costs of mate guarding with soft shell BC males. Results obtained from the third trial suggested that a newly-moulted female can discriminate male morphotypes (SM, OC and BC) from their pheromone cues. This indicates that male morphotypes release pheromones which differ from each other in some way. Newly-moulted females responded positively to both SM and BC males with different levels of attraction with the greatest attraction to BC males to BC males suggesting that pheromone released from the BC male may carry information relating to dominance status. Urine is believed to be one of the main carriers of pheromone and is usually released from the antennal gland. Different urine concentrations (0.1, 1.0, 2.0, 3.0, 5.0 and 10µl l-1) of collected urine from BC males were used to test the sexual attraction behaviour of receptive newly-moulted females. Also, the attractant capability of fresh urine following exposure to different temperature regimes (cooled at 4ºC, frozen at -70ºC and heated at 70ºC) was tested. Since newly-moulted female M. rosenbergii were attracted to BC male urine, this indicates the existence of sex pheromone in the fresh urine. Also, it was found that the sexual response of females to fresh urine of BC males was directly proportional to urine concentration with faster responses observed with increasing urine concentrations. At the three fresh urine concentrations 0.1 µl l-1, 1.0 µl l-1 and 2.0 µl l-1, statistical analysis indicated no significant difference (p>0.05) between these three concentrations while a significant (P<0.05) response was to concentrations more than 3.0 µl l-1. This may indicate that these three concentrations were not sufficient to elicit attraction behaviour in newly-moulted females. A concentration of 3.0 µl l-1 of fresh urine is suggested to be a sufficient concentration to elicit a significant sexual attraction under laboratory conditions. Response of newly-moulted female prawns to the various temperature treatments tested declined in response to nominally increasingly degradative treatments. Also, statistical analysis showed that temperature treatment and concentration added both had a significant effect on the response of females. The greatest degradation of urine attractiveness was found with the 70ºC heat treatment. It can be concluded that the pheromone components of prawn urine are friable when exposed to high temperatures. Using light and transmission electron microscopes, ultrastructural observation of the antennal gland (AG) of M. rosenbergii suggests that it has four distinct regions, the coelomosac, the nephridial tubules, the labyrinth and the bladder. Morphological and functional descriptions of each of these regions were compared with those of other aquatic Crustacea.

African mole-rats (Bathyergidae) exhibit a wide range of social structures ranging from solitary to eusocial. This allows for studies looking at links between sociality and measurable characteristics such as spatial learning and kin-recognition. Furthermore, the existence of species with differing level of sociality allows for comparison between the highly social species and the solitary species. The existence of differences in spatial learning ability and memory between the sexes has long been debated. Eusocial Damaraland mole-rats (Cryptomys damarensis) and solitary Cape mole-rats (Georychus capensis) were tested to see if there were sex or species differences in the ability to locate food in an artificial maze task with the express purpose of investigating spatial learning and memory. Measurements of the time taken to complete the task, the distance travelled, wrong turns taken, and the average velocity at which animals travelled were used to compare performance between animals. Both sexes in each of the species exhibited learning and a decay in memory over time. The Damaraland mole-rat exhibited superior learning and memory retention when compared to the Cape mole-rat. Male Cape mole-rats had superior learning and longer term memory retention when compared to females of the same species. There was no significant difference in learning curves between male and female Damaraland mole-rats, but this species did exhibit a tendency for females to show better medium term memory retention while males performed better on long term memory trials. Species differences are likely to be linked to social organization and possibly the resultant burrow-structure in the natural environment, while sex-differences may be due to differing life histories. Kin-recognition is important in maintaining the social structure and hierarchy in the eusocial species of African mole-rat, Cryptomys damarensis. Opposite sex sibling pairs from reproductively quiescent colonies were tested to see if exposure to colony urine odour would reinforce recognition of opposite sex siblings and the concomitant incest avoidance. Control sibling pairs from the same colonies were exposed to water. Mating, social, and non-social behaviours were measured in all sibling pairs. In addition, urinary levels of cortisol, progesterone and testosterone were measured to examine the interaction between four factors: colony olfactory cues (urinary odour), hormone levels, mating behaviour and relatedness. Exposure to urinary odour reinforced recognition and was correlated to a decrease in mating behaviour. Hormonal assays suggest that female hormone levels are modified based on exposure to colony urine odour, while males are not affected. Olfactory cues such as colony urinary odour is linked to the alteration and correlation of hormone levels and mating behaviour. The Damaraland mole-rat and other species in the family Bathyergidae provide a useful system for investigating aspects of learning and memory, as well as the potential correlation between cognitive processes and sociality. / Dissertation (MSc (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted