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Doctor of Philosophy / Department of Entomology / David C. Margolies / James R. Nechols / Foraging traits such as prey consumption rate and the efficiency with which predators convert their prey into offspring are important determinants of local predator-prey dynamics. However, in environments with patchy prey distribution, predator dispersal and aggregation in response to prey-induced volatile cues becomes more critical. My dissertation addressed predator-prey population dynamics in response to variation in four foraging traits in the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae): consumption rate, conversion efficiency, dispersal, and olfactory response related to prey. The dispersal response and olfactory sensitivity in predatory mites is modified by prey-related cues. For example, the dispersal response increased with decreasing prey density in a patch and increasing prey-related volatiles from outside the prey patch. The olfactory response of predatory mites also increased with increasing numbers of prey per plant or with the length of time a plant was infested by prey. These results formed the basis for development of bioassays used to examine genetic variation in dispersal and olfactory response of predatory mites. Through artificial selection I documented additive genetic variation in all four traits. After relaxation of selection, high-level phenotypes were stable compared to their low counterparts. There were significant genetic correlations between some of the foraging traits. However, there were no correlations between foraging traits and life-history traits. The existence of genetic variation and covariation among the foraging traits suggests that predatory mites must be able to adopt different foraging strategies in the evolution of prey-finding in a tritrophic system. High consumption, high conversion efficiency and high dispersal response phenotypes interacted differently with prey in a spatially complex landscape. All foraging traits were comparable in terms of predator-prey densities and plant damage; but they were lower than the unselected control. Spatial association and correlation analysis showed that all foraging traits were positively associated with prey; but the strongest association was observed for the high conversion efficiency and dispersal lines. The variability in foraging behaviors of the predatory mite affects its ability to locate patchily distributed prey, thereby influencing foraging efficiency and population dynamics. This research provides new information about the critical link between predator foraging and population dynamics relevant to biological control.

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Several attempts have been made to reduce Botrytis cinerea grey mould in vineyards and in storage by means of biological control. However, the so called "silver bullet" approach in utilising a single antagonist, has its limitations when compared with synthetic fungicides. Often the antagonist has a limited spectrum of activity and the duration of its effectiveness is less than that provided by synthetic fungicides. Furthermore, antagonists are more likely to be effective in preventing initial infection rather than resumption of latent infection. Therefore, due to the various infection sites in grape bunches utilised by B. cinerea and the fact that the pathogen can remain latent in the grapevine tissue, it may be possible to obtain effective control of the pathogen by integrating fungicides and different biological control agents each aimed at a different site in grape bunches, protecting the bunch at the various phenological stages of growth and under different micro climatic conditions. In this study the potential of three fungal antagonists (Glioc/adium roseum, Uloc/adium atrum and Trichoderma harzianum) and one yeast (Trichosporon pullulans) to colonise different sites in grape bunches, and to reduce B. cinerea infection, was investigated in commercial vineyards. As the biological control agents were used in an integrated system, the effect of various fungicides frequently applied to local vineyards on the organisms was also investigated. Fungicide trials were conducted taking into account two possible scenarios. Firstly, the possible effect of fungicides applied to the vineyard after an application of the biological control agent or shortly before the application of the biocontrol agent. This entailed exposing the biocontrol agents to relatively low concentrations of the active ingredient of the fungicides, similar to the residue levels to which these organisms would be exposed under field conditions. Secondly, the possibility of applying the organisms and the fungicides at the same time by making use of spray tank mixtures. This meant exposing the biocontrol agents to relatively high doses of the active ingredient of the various fungicides. Mycelial growth and germination tests were performed on agar in Petri dishes to determine the effect of fungicides. It was assumed that if the fungicide effectively inhibits the antagonist at 2.5 !-lg a.Uml, the fungicide and antagonist can not be used in an integrated programme. Based on this criterium, T harzianum can not be applied to vineyards with penconazole, mancozeb/metalaxyl, pyrifenox or mancozeb. In addition T harzianum can not be applied as tank mixtures with iprodione. However, T harzianum can be used in conjunction with pyrimethanil, folpan, iprodione, fosetyl-Al and copperhydroxide, provided the chemicals and the antagonist are applied alternately. Gliocladium roseum can not be applied in a tank mixture with pyrimethanil and penconazole, but can be used on grapevine in conjunction with penconazole, pyrifenox, pyrimethanil, iprodione and fosetyl-Al. Ulocladium atrum can not be applied with pyrimethanil and iprodione. Ulocladium atrum can be applied in conjunction with penconazole, pyrifenox, pyrimethanil, iprodione, fosetyl-Al and mancozeb. The fungus can be applied in a tank mixture with penconazole and pyrifenox. The antagonists were applied as conidial suspensions to bunches at various phenological stages in commercial vineyards planted with the wine grape cultivar Chardonnay in the Stellenbosch region, or the table grape cultivar Dauphine planted in Paarl region. Bunches were collected 2 wk after application, surface-sterilised and used for determining antagonist colonisation and B. cinerea infection at specific sites in the bunches. In Chardonnay, the antagonists colonised the different sites, but colonisation during the three seasons was inconsistent and sporadic. Ulocladium atrum and G. roseum colonised floral debris to a degree in the 1996 season. However, in the 1997 season these two antagonists did not develop from floral debris. Trichoderma harzianum colonised floral debris extensively in the 1996 season. In the 1997 season colonisation by T harzianum dropped, but unlike G. roseum and U atrum, T harzianum occurred at a low level in flowers. Ulocladium atrum only colonised bunches during bloom, and was not found in bunches monitored from pea-size stage to véraison. This finding suggests that the saprophyte colonised moribund and dead flower parts occurring in bunches during full bloom to the pre-pea size stage, and is not likely to be found in living tissue. Gliocladium roseum colonised grape berries and pedicels to some degree and T harzianum colonised these grape parts extensively. Botrytis cinerea occurred inconsistently and at low frequencies in the different sites in bunches. It was therefore not possible to comment on the effectivity of the various antagonists in the three seasons during which the trials were performed. However, it was noted that, during the peasize stage in 1996, when high levels of B. cinerea were recorded, T harzianum controlled these infections in the pedicels more effectively than any other treatment. / AFRIKAANSE OPSOMMING: ONDERDRUKKING VAN BOTRYTIS CINEREA DEUR ANTAGONISTE IN LEWENDE, AFSTERWENDE EN DOOIE WINGERDWEEFSEL Die benadering om Botrytis cinerea verrotting van wingerd met behulp van 'n enkele biologiese beheeragent in plaas van met sintetiese fungisiede te beheer, het sekere beperkinge. Antagoniste het dikwels 'n beperkte spektrum van aktiwiteit, en die duur van hul effektiwiteit is minder as dié van fungisiede. Antagoniste is gewoonlik ook minder effektief in die beheer van latente infeksie. Die patogeen het verder die opsie om druiwetrosse deur verskillende infeksieweë te koloniseer. Fungisiede kan druiwetrosse beter teen infeksie deur veelvuldige infeksieweë beskerm as 'n enkele antagonis. In die lig hiervan is die beheer van die patogeen deur 'n kombinasie van fungisiede en verskillende biologiese beheeragente, wat elk gemik is om 'n ander infeksiepunt in die druiwe te beskerm, ondersoek. Drie swamagtige antagoniste (Glioc/adium roseum, Uloc/adium atrum en Trichoderma harzianum) en een gis (Trichosporon pullulans) is in die ondersoek gebruik. Voorloper ondersoeke, waar twee moontlike scenarios in ag geneem is, is met fungisiede uitgevoer. In die eerste scenario is die effek van fungisiede, aangewend op wingerd kort vóór aanwending van die biologiese beheeragent, of kort ná aanwending, ondersoek. Hierdie proef het die blootstelling van die biologiese beheeragent aan relatief lae konsentrasies van die aktiewe bestanddeel van die fungisied, vergelykbaar met residuvlakke waaraan die organismes onder veldtoestande blootgestel sou word, behels. Tweedens is die moontlikheid om antagoniste en fungisiede gelyktydig as spuitpompmengsels toe te dien, ondersoek. In hierdie proef is die biologiese beheeragente aan relatief hoë dosisse van die aktiewe bestanddeel van verskillende fungisiede blootgestel. Miseliumgroei en ontkiemingstoetse is op agar in Petribakkies uitgevoer om die effek van die fungisiede te bepaal. As kriterium is aanvaar dat indien 'n fungisied die antagonis effektief by 2.5J..lglml aktiewe bestanddeel inhibeer, die fungisied en antagonis nie in 'n geïntegreerde program gebruik kan word nie. Gebaseer op hierdie kriterium kan T harnzianum nie aangewend word in 'n wingerd wat met penconazole, mancozeb/metalaxyl, pyrifenox of mancozeb behandel is nie. Ook kan T harzianum nie in 'n spuitpompmengsel met iprodione aangewend word nie. Trichoderma harzianum kan egter saam met pyrimethanil, folpan, iprodione en fosetyl-Al gebruik word, mits dié chemikalieë en die antagonis afwisselend aangewend word. Glioc/adium roseum kan nie in 'n spuitpompmengsel met pyrimethanil en penconazole aangewend word nie, maar kan saam met penconazole, pyrifenox, pyrimethanil, iprodione en fosetyl-Al gebruik word. Uloc/adium atrum kan nie saam met pyrimethanil, iprodione en fosetyl-Al gebruik word nie. Die swam kan wel in 'n spuitpompmengselmet penconazole en pyrifenox aangewend word. In verdere proewe is die antagoniste as spoorsuspensies op trosse op verskillende groeistadia in kommersiële wingerde, wat met die wyndruitkultivar Chardonnay of die tafeldruifkultivar Dauphine aangeplant is, ondersoek. Trossies is twee weke na toediening versamel, oppervlakkig gesteriliseer en gebruik om vlakke van antagoniskolonisasie en B. cinerea infeksie op spesifieke nisse in die trosse te bepaal. In die geval van Chardonnay het die antagoniste die verskillende nisse gekoloniseer, maar die kolonisasie was sporadies en nie konstant gedurende die drie seisoene van ondersoek nie. Uloc/adium atrum en G. roseum het blomdeeltjies tot 'n beperkte mate in die 1996 seisoen gekoloniseer, maar nie in die daaropvolgende seisoen nie. Daarteenoor het T. harzianum blomdeeltjies ekstensief in die 1996 seisoen gekoloniseer, en in 'n beperkte mate in die daaropvolgende seisoen. Uloc/adium atrum kon nie trosse van ertjiekorrelgrootte tot deurslaan vestig nie. Hierdie bevinding dui daarop dat die saprofiet afsterwende en dooie blomdeeltjies, wat van volblom tot ertjiekorrelstadium in die trosse voorkom, koloniseer, maar dat dit nie in lewende weefsel voorkom nie. Daarteenoor het T. harzianum die verskillende trosdele ekstensief gekoloniseer. Botrytis cinerea het gedurende die drie seisoene wisselvallig en teen lae frekwensies in die verskillende nisse in die trosse voorgekom. Dit was gevolglik nie moontlik om 'n konkrete afleiding oor die effektiwiteit van die verskillende antagoniste as biobeheeragente van B. cinerea te maak nie. In die geval van Dauphine was die onderskeie organismes swak koloniseerders van blomdeeltjies. Trichoderma harizanum kon egter die lewende trosdele koloniseer. Kolonisasievlakke was laag en was nooit meer as 50% nie. In beide seisoene het die kolonisasievermoë van T. harzianum drasties ná trostoemaak gedaal. Daarteenoor het beide G. roseum en U atrum tydens al die ontwikkelingstadia die lewende trosdele swak gekoloniseer. Botrytis cinerea het ook uiters sporadies en teen baie lae vlakke voorgekom. Die bevindinge het getoon dat klimaatsomstandighede wat in tafeldruifwingerde in die Wes-Kaap heers, nie geskik is vir die vestiging van die biologiese beheeragente wat in die studie ondersoek is nie.

The optimisation of spore production by the potential fungal biological control agent for aphids, Erynia neoaphidis Remaudiere and Hennebert (Zygomycetes: Entomophthoraceae) was studied. The fungus was able to grow in semi-defined Frynia medium (SDEM) containing glucose, yeast extract, mycological peptone, and 0.02% oleic acid buffered to a pH 6. Oleic acid was fungicidal at 0.1 % (v/v) while 0.02% (v/v) oleic acid was the optimum for radial grovvth. Plugs cut 5-10 mm from the margin ofa colony produced more conidia than plugs cut 13-20 mm from the colony margin. Renewed grovvth continued through two subcultures on solid SDEM lacking yeast extract (SDEML YE), and SDEM lacking mycological peptone (SDEMLMP). The continued growth was attributed to the carry over of nutrient in the inoculum. Growth was supported on SDEMNH4S04 when ammonium sulphate was used as the nitrogen source instead of mycological peptone suggesting that the fungus could obtain the growth factors it required from yeast extract. When chitin was added to SDEM in insoluble powder form instead ofglucose (SDEMC 1 & SDEMC2), the absence of a clearing zone around the developing colony suggested that chitin was not metabolised by E. neoaphidis. Biomass grown on SEMA and on SDEMDG (containing double the original concentration ofglucose 3 2grl), resulted in production of fewer conidia oflarger volume compared to SDEMDMP containing double and half the original concentration of mycological peptone (SDEMHP), SDEM containing halfthe original concentration ofglucose (SDEMHG). Increasing the glucose to double the original concentration resulted to an increase in biomass. Erynia neoaphidis grown on aphid cadavers produced many, smaller conidia. Mycelial mats harvested from biomass grown in fed-batch liquid fermenter culture in SDEMDG at the end ofthe exponential phase and placed on water agar discharged conidia at a rate of 6,700 conidia mm -2 h-1which persisted for approximately 3 days. When E. neoaphidis was subcultured onto SDEM from SEMA medium, the colony growth rate increased on the second subculture on SDEM where more lipases and aminopeptidases were detected at higher concentrations using the API ZYM system. This shows that attenuation might have taken place by either a phenotypic or genotypic (eg mutation) change or both when E. neoaphidis was grown on SDEM from SEMA medium. Growth in GASP medium resulted in the production of more biomass and a delay in the onset of decline phase compared to cultures grown in SDEM. Fewer enzymes were detected at a lower concentration in cultures grown in GASP compared to cultures grown in SDEM, this difference might be more likely to relate to the balance of nutrients and the fact that GASP medium is more similar in composition to the nutrients found in the haemocoel of an aphid. Based on this research. It is recommend that E. neoaphidis be grown in SDEM liquid cultures containing 32 grl glucose instead of 16 grl glucose. Biomass for field applications should be harvested at the end ofthe exponential growth and mycelial mats made. The mycelial mats should be maintained at high relative humidity and can be expected to discharge conidia for 3 days.

Thesis (MScAgric (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / Codling moth (CM), Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae), is the major pest of apples and pears in the South Western Cape, South Africa. Apart from conventional insecticide sprays, area-wide biologically intensive control methods, such as Sterile Insect Technique (SIT) and pheromone mediated mating disruption (MD) are currently in use on two farms in the Elgin valley. The indigenous parasitoid Trichogrammatoidea lutea Girault (Hymentoptera: Trichogrammatidae) attacks eggs of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), as well as CM and has been found to have considerable parasitism potential on both. Elevated host egg numbers, as achieved by SIT are thought to support establishment of populations of these natural enemies in the orchards. For rapid and secure Trichogrammatoidea species identification, the ITS2 sequences of Trichogrammatoidea lutea and T. cryptophlebiae Nagaraja (an indigenous FCM parasitoid on citrus) were determined and species specific primers were developed. Lifetable studies of T. lutea indicated an optimal temperature for reproduction at around 20 °C. Food was provided by the application of honey-solution soaked cotton wool, behind fine netting. The effect of food provision by this method was found to be dependent on temperature. The acceptance of CM eggs from sterilized vs. fertile parents and of radiation-sterilized eggs vs. fertile ones was assessed in choice trials. While no difference was observed between radiated and fertile eggs, sterile eggs from irradiated parents were significantly less attractive than eggs from fertile parents. In several field studies the dispersal capacity and population sustainability of released T. lutea were investigated. Trials took place in apple and pear orchards in the Elgin valley that formed part of an area-wide sterile CM SIT program. Most of the wasp releases were carried out within blocks of up to 1 ha. A square grid of up to 36 monitoring trees per block allowed spatial distribution analysis. Following single central point releases, parasitism of sentinel eggs was recorded until the end of all experiments, the longest of which lasted 37 weeks. T. lutea females were found to disperse up to 73 m, within one week. Studies concerning toxicity of four commonly used insecticides and one fungicide to immature and adult T. lutea indicated no to low susceptibility of wasps at egg- to first-instar-stage within host eggs. Contact toxicity of the tested materials to adults differed significantly, depending on the compound. All five pesticides caused significantly higher mortality among adults relative to the control. The overall aim of above studies was to determine the potential of T. lutea for broad-scale releases against CM, within a broader integrated pest management program in apple and pear orchards in the Western Cape.

Thesis (MScAgric (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / The codling moth, Cydia pomonella (L.), is a key pest in pome fruit orchards in South Africa. In the past, broad spectrum insecticides were predominantly used for the local control of this moth in orchards. Concerns over human safety, environmental impact, widespread dispersal of resistant populations of codling moth and sustainability of synthetic pesticide use have necessitated the development and use of alternative pest management technologies, products and programmes, such as the use of entomopathogenic nematodes (EPNs) for the control of codling moth. Entomopathogenic nematodes belonging to either Steinernematidae or Heterorhabditidae are ideal candidates for incorporation into the integrated pest management programme currently being developed for pome fruit orchards throughout South Africa with the ultimate aim of producing residuefree fruit. However, these lethal pathogens of insects are not exempted from governmental registration requirements and have therefore not yet been commercialized in South Africa. A nontarget survey was conducted to find suitable isolates of EPNs from local soils and to test their effectiveness as control agents against the codling moth. Soil samples were collected from several habitats and regions throughout South Africa and nematodes were recovered using the insect baiting technique. All EPN isolates obtained were identified to species level using a molecular taxonomic approach. Entomopathogenic nematodes were recovered from 20 of the 200 soil samples (10 %). Of these, eight (40 %) yielded Steinernema spp., identified as three isolates of S. khoisanae and five undescribed Steinernema spp. The other 12 (60 %) of the samples were positive for Heterorhabditis spp. and included six isolates of H. bacteriophora, five H. zealandica and one H. safricana. These isolates were then evaluated in laboratory bioassays for their potential as microbial agents of codling moth under varying conditions. A morphometric study indicated that all natural openings (mouth, anus and spiracles) of final instar codling moth were large enough for the infective juveniles (IJs) of all tested EPN species to gain entry into the larvae.

Natural enemies are members of complex ecological communities, and their ability to contribute to the biological control of pest organisms is strongly influenced by a convoluted network of ecological interactions with many other organisms within these communities. Researchers must develop an understanding of the mechanisms that shape trophic webs to predict and promote top-down effects of predators. The behavior of predators can have a strong influence on their potential as biological control agents. Web-building spiders are a useful example organism for the study of natural enemy behavior because of the experimentally tractable nature of their foraging behavior. Specifically, patterns in microhabitat utilization and web construction by spiders provide insights into foraging behavior and pest-suppression potential. In field collections, spiders were found to utilize microhabitats in a species-specific manner. Molecular gut-content analysis and a mathematical model showed that two spiders belonging to different web-building guilds differed in their dependence on microhabitat-specific prey activity-densities. In particular, the sheet-weaving guild constructed webs in microhabitats with the highest densities of springtails (Collembola). High dependence on this non-pest prey also correlated with evidence of increased intraspecific competition, and implies a potential negative effect of springtails on the consumption of pest insects, such as aphids. In laboratory two-choice assays, sheet-weaving spiders selected microhabitats and constructed webs in a flexible, stepwise manner, which allowed spiders to regulate their investment of silk resources to match the profitability of the microhabitat. Spiders also exhibited prey-specific shifts in foraging behavior, constructing webs in the presence of mobile, non-pest springtails, but utilizing active foraging tactics in the presence of sedentary, pest aphids. However, in factorial no-choice assays, pest-consumption rates were not significantly affected by the presence of non-pest springtails, indicating that prey-specific foraging-mode shifts are compatible with biological control. From these results, it is clear that the flexible foraging behavior of web-building spiders has a strong influence on their roles in ecological communities and their position within food webs. This dissertation highlights the importance of understanding the nuances of natural-enemy behavior for properly assessing and promoting biological control services.

A strategy for the discovery of new insect growth regulators from arid lands plants was developed. Plant genera with a history of toxicity, medicinal use, or incorporation in native american cultures were selected. Forty-five species from twenty-one families were collected, extracted, and tested for biological activity on the large milkweed bug, Oncopeltus fasciatus. Eight extracts were toxic and the extract of Nama hispidum (Hydrophyllaceae) caused nymphs to undergo precocious metamorphosis to an adult. The active component of N. hispidum was precocene II (6,7-dimethoxy-2,2-dimethyl chromene). Nine Nama species, representing four of the five sections in the genus were gathered from Hawaii, California, Nevada, Arizona, New Mexico, and the Dominican Republic. In addition to the insect anti-hormone, precocene II (PII), present in N. hispidum, N. rothrockii contained at least two different insect juvenile hormone mimics, and N. sandwicense contained insect anti-hormone and insect juvenile hormone mimics. Fifth instar larvae of Heliothis zea were used as model insects to distinguish between post-ingestive intoxication and feeding deterrency during exposure to PII. Larvae fed artificial diet with PII were deterred from eating, and had retarded weight gain, growth, and development. Insects grown on diet with PII consumed less food, could not digest the food, or convert ingested food to body mass. in vivo radiotracer studies with the nutrient, ¹⁴C linoleic acid, show a lower rate of transport and incorporation of radioactivity into fat body tissue. A change in the midgut epithelial cells from PII resulted in reduced transport efficiency and retarded larval growth and development. Scanning electron microscopy of the midgut epithelia indicated that cytotoxic damage is induced by PII. Observed changes in the midgut epithelial cells are consistent with a destructive alkylation of cell structures by PII.

Various biological relationships between the myramid egg parasite, Anaphes ovijentatus (Crosby and Leonard), and its hosts were studied. Eggs of the four major species of Lygus that occur on crops were highly parasitized. Other mirid hosts in southern Arizona were collected from weeds in agricultural areas. Small numbers of Nabis alternatus Parshley and N. americoferus Carayon, predators of several insect pests, were parasitized in the laboratory. The membracid Spissistilus festinus (Say) was an infrequent host. Parasitism of L. hesperus was similar (82-88%) for eggs 1-6 days old at 25°C, but parasitism of 7-day-old eggs was significantly reduced (18.9%). Parasitism must occur at least 24 hours prior to host egg hatch to be successful; the period of time required for A. ovijentatus egg development. Anaphes ovijentatus developed from egg to adult in L. hesperus eggs at a constant temperature of 12.8°C and at variable regimes with means of 12.8, 10.6, and 32.8°C. An average of 26 progeny per female were produced at the variable 12.8 and 10.6°C regimes, only a few progeny were produced at a constant 12.8°C and none were produced at the variable 32.8°C regime. Lygus hesperus eggs hatched at all four temperature regimes, but nymphs survived to adulthood only at the variable regimes of 12.8 and 10.6°C. Total egg to egg periods at the variable 12.8°C was approximately 103 days for L. hesperus and about 54 days for A. ovijentatus. The majority of the L. hesperus eggs were deposited in the upper halves of cotton, alfalfa, and the crucifer Sisymbrium irio L. plants. L. hesperus deposited more eggs in alfalfa than in cotton plants, but showed no preference between alfalfa and S. irio. Anaphes ovijentatus did not demonstrate clear preferences for L. hesperus eggs in any plant species or plant section.

Temperature effects on the biology of Tetranychus cinnabarinus (Boisduval) and Typhlodromus occidentalis (Nesbitt) (Acarina: Phytoseiidae) were studied in the laboratory. Temperature had a definite effect on the developmental time, longevity and survival of adult females, and duration and rate of oviposition in both T. occidentalis and T. cinnabarinus. Increases in temperature significantly decrease developmental time, pre-oviposition periods, oviposition duration and rate, and the longevity and survival rates of both adult females. However, the daily consumption rate of T. occidentalis protonymph, deutonymph and adult gravid female increased significantly with an increase in temperature. Mean generation times decreased for both mites with an increase in temperature. The intrinsic rate of natural increase rose with each temperature increase. However, the r(m) of T. occidentalis was less than that for T. cinnabarinus at all temperature regimes, and it decreased from the 26.6° C regime to the 30.5° C regime. Of the three temperatures studied, 22.7°, 26.6°, and 3.5° C, 22.7° C proved to be the optimum for the predator to maintain control over the prey.