Building design, maintenance, and management can have significant impacts on accessibility and suitability for pest species. The brown marmorated stink bug, Halyomorpha halys (Stål), causes household nuisance pest problems because of its habit of using human homes as winter refuges. Studies were conducted to understand behaviors and characteristics relevant to this problem, including response to gravity, ability to pass through openings, responses to heat, and mortality estimations in wall assemblies. In the lab, winter shelter seeking bugs were shown to exhibit upward movement, and field observations of bugs on building exteriors gave similar results. In experiments testing the size limits on openings through which bugs could pass, height limited tests excluded most females at 4 mm, and all bugs at 3 mm. Pronotum width limited tests excluded most females at 8 mm and nearly all bugs at 7 mm. Accompanying measurements of over 900 bugs found an average female pronotum width of 8.33 mm and height of 4.03 mm, and male pronotum width of 7.47 mm and height of 3.50 mm, with minimum sizes indicating that only a small percentage of bugs will pass the smallest openings tested. Heat response experiments of shelter seeking bugs were first piloted outdoors, and then modified to be a forced choice indoor test. In outdoor tests on a flat plane wall section with alternating heated sections, bugs did not respond to thermal contrast but rather immediately walked off of the wall. In the indoor forced choice test, a box of four cavity walls was used. Bugs did not respond to the heated sections in either the adjacent or opposite configuration. Thermal simulation modeling was used to evaluate the possible effects of varying wall assembly materials and configurations on cold-related mortality of bugs overwintering in the cavity space behind cladding. Simulation results indicated that bugs electing to overwinter in the space between cladding and sheathing were at risk of freezing deaths, with mortality expectations increasing in better insulated buildings. The results of these studies will inform future control measures and impact studies in buildings. / Ph. D. / Building design, maintenance, and management can have significant impacts on accessibility and suitability for pest species. The brown marmorated stink bug, Halyomorpha halys (Stål), is a household pest because of its habit of using human homes as winter refuges. This research investigated the ability of these bugs to enter homes, and what happens once inside. This included responses to gravity and heat, studies of the body size and the ability to enter openings in building envelopes, and estimations of mortality due to freezing in wall assemblies using thermal simulation modeling. Bugs were shown in the laboratory and on the sides of buildings to consistently move upward. Bugs were given the ability to move along alternatingly heated and unheated sections of walls in search of winter shelter. The heated sections of walls did not elicit any response, suggesting that warmer portions of walls are not impacting the search for structure entrances. Bugs were shown to not pass through 3 mm tall or 7 mm wide openings, though female bugs tend to require even larger holes. Males are consistently smaller than females, at an average of 3.50 mm tall and 7.47 mm wide to the females’ average 4.03 mm height and 8.33 mm width. Thermal simulation modeling suggested that increasing the insulation in a building may influence the expected mortality rate of bugs that overwinter in the space between sheathing and cladding. These findings will help to create and target pest control methods, by helping design exclusion methods, identifying what openings need treatment, and indicating better orientations of traps. The thermal modeling results suggest possible effects of building design choices on the spread of H. halys, as well as possible problems associated with increased mortality within wall assemblies.

<p>Kukuruzni plamenca (<em>Ostrinia nubilalis</em>, Hbn.) je vrsta umerenog klimatskog područja&nbsp;<br />koja niske zimske&nbsp; temperature preživljava ulaskom u dijapauzu u stadijumu gusenice.&nbsp;Dijapauza i otpornost na hladnoću (cold hardiness,&nbsp; eng.), kod mnogih insekatskih vrsta često&nbsp;predstavljaju esencijalne, tesno povezane komponente strategije preživljavanja delovanja&nbsp;niske temperature, kao &scaron;to je to slučaj i kod kukuruznog plamenca&nbsp; <em>Ostrinia&nbsp; nubilalis</em>, Hbn. U&nbsp;okviru grupe insekata otpornih na hladnoću, svrstava se u insekte otporne na zamrzavanje&nbsp;(freeze tolerant,&nbsp; eng.) jer su&nbsp; sposobne da prežive ekstracelularno zamrzavanje telesnih&nbsp;tečnosti.</p><p>Iako se o osnovnim strukturnim i metaboličkim de&scaron;avanjima u dijapauzi insekata već dosta&nbsp;zna, jo&scaron; uvek postoje brojne dileme o ovom vidu preživljavanja insekata u nepovoljnim&nbsp;uslovima sredine, posebno sa aspekta izloženosti niskim zimskim temperaturama i&nbsp;mehanizmima krioprotekcije. Zbog toga je&nbsp; cilj ove doktorske disertacije&nbsp; bio&nbsp; da se sa aspekta&nbsp;biofizičkih osobina lipida i sastava masnih kiselina: &nbsp;odrede biofizičke osobine (temperature&nbsp;faznog prelaza) ukupnih lipida nedijapauzirajućih i dijapauzirajućih gusenica tokom dijapauze&nbsp;(početak, sredina i kraj),&nbsp; kao i u kontrolisanim uslovima hlađenja dijapauzirajućih gusenica;&nbsp;zatim da se&nbsp; odredi zastupljenost pojedinih klasa lipida u hemolimfi i masnom telu&nbsp;nedijapauzirajućih i dijapauzirajućih gusenica;&nbsp; da se&nbsp; utvrde promene sastava masnih kiselina&nbsp;strukturne (polarne) i rezervne (nepolarne)&nbsp; frakcije&nbsp; lipida celih gusenica&nbsp; tokom dijapauze i&nbsp;pod uticajem različitih temperatura u eksperimentalnim uslovima; kao i da se&nbsp; odredi tkivna&nbsp;specifičnost, hemolimfe i masnog tela, masnih kiselina ukupnih lipida&nbsp; i&nbsp; biofizičke&nbsp; osobine&nbsp;ukupnih lipida masnog tela nedijapauzirajućih i dijapauzirajućih gusenica tokom dijapauze,&nbsp;kao i u kontrolisanim uslovima hlađenja dijapauzirajućih gusenica.&nbsp;&nbsp;</p><p>U analizi lipida kukuruznog plamenca <em>Ostrinia nubilalis</em>, Hbn. kori&scaron;ćene su sledeće tehnike:&nbsp;tankoslojna hromatografija (TLC) sa skenirajućom denzitometrijom, za razdvajanje i analizu&nbsp;klasa lipida;&nbsp; zatim&nbsp; gasno-masena hromatografija (GC-MS), za analizu masnih kiselina kao i&nbsp;diferencijalna skenirajuća kalorimetrija (DSC&nbsp; &ndash;&nbsp; differential scanning calorimetry,&nbsp; eng.), za&nbsp;termalnu analizu ekstrahovanih lipida.</p><p>Kod&nbsp; gusenica <em>Ostrinia&nbsp; nubilalis</em>&nbsp;sastav&nbsp; masnih kiselina ukupnih lipida analiziranih tkiva i&nbsp;lipidnih frakcija značajno se razlikuje između&nbsp; ova dva fiziolo&scaron;ka stanja, stanja dijapauze i&nbsp;nedijapauze.&nbsp; Dijapauza indukuje značajno povećanje sadržaja mononezasićenih masnih&nbsp;kiselina, pre svega palmitoleinske (16:1n-7) i oleinske masne kiseline (18:1n-9) uz&nbsp;istovremeno smanjenje sadržaja zasićenih i&nbsp; polinezasićenih masnih kiselina, pre svega&nbsp;palmitinske (16:0) i linolne masne kiseline (18:2n-6).&nbsp; Temperature faznog prelaza ukupnih&nbsp;lipida celih gusenica i masnog tela&nbsp; značajno su niže kod dijapauzirajućih gusenica&nbsp; <em>O.&nbsp;nubilalis</em>,&nbsp; usled &nbsp;značajnog povećanja&nbsp; stepena nezasićenosti masnih kiselina u njihovom&nbsp;sastavu. Značajno niže temperature&nbsp; faznog prelaza lipida dijapauzirajućih gusenica&nbsp; <em>O.<br />nubilalis</em>&nbsp; rezultat su povećanja stepena nezasićenosti njihovih masnih kiselina. Možemo&nbsp;zaključiti da su&nbsp; promene u sastavu&nbsp; masnih kiselina lipida indukovane dijapauzom važna&nbsp;komponenta preživljavanja niskih temperatura kod&nbsp; <em>O. nubilalis</em>&nbsp; Hbn. jer se&nbsp; veliki deo lipida&nbsp;održava u tečnom stanju čak i na temperaturama daleko ispod 0&deg;C, &scaron;to je neophodno za&nbsp;održavanje njihove fluidnosti odnosno funkcionalnosti.</p> / <p>European corn borer (<em>Ostrinia nubilalis</em>,&nbsp; Hbn.)&nbsp; inhabiting temperate regions&nbsp; that&nbsp;survive low winter temperatures as a diapausing fifth instar larva.&nbsp; Diapausing larvae are cold&nbsp;hardy and freeze tolerant as they are able to survive the extracellular formation of ice crystals.&nbsp;Winter survival for many insect species living in seasonally cold environments includes a&nbsp;radical remodeling of metabolism. This implies entry into a developmentally arrested,&nbsp;hypometabolic state of winter diapause, which in <em>O. nubilalis</em>&nbsp; and&nbsp; many&nbsp; other&nbsp; insect species&nbsp;of these habitats is closely related to their cold hardiness.</p><p>Although the basic structural and metabolic events consider insect diapause is already known,&nbsp;there are still many doubts about the survival of insects in an unfavorable environment,&nbsp;particularly in terms of&nbsp; exposure to low winter temperatures &nbsp;and mechanisms of&nbsp;cryoprotection. Therefore, the aim of this thesis in terms of biophysical properties of lipids&nbsp;and fatty acid compositions,&nbsp; was to: i) to determine &nbsp;the biophysical properties (phase&nbsp;transition temperatures) of the total lipids of non-diapausing&nbsp; larvae&nbsp; and diapausing larvae&nbsp;during diapause (early diapause, mid diapause and termination of diapause), as well as under&nbsp;controlled cooling conditions during different phases of diapause; ii) to determine the fatty&nbsp;acid compositions of structural (polar) and storage (non-polar)&nbsp; total&nbsp; lipid fractions of non-diapausing&nbsp; larvae&nbsp; and diapausing larvae, as well as under the influence of different&nbsp;<br />temperatures during diapause in the controled experimental conditions; iii)&nbsp; to determine the&nbsp;lipid classes&nbsp; composition of total lipids extracted from the haemolymph and fat body of non-diapausing and diapausing larvae;&nbsp; iiii) to determine&nbsp; the haemolymph and fat body total lipid&nbsp;fatty acid compositions&nbsp; as well as the biophysical properties of the fat body total lipids of&nbsp;non-diapausing larvae&nbsp; and diapausing larvae during diapause as well as in terms of controlled&nbsp;cooling conditions. Thus, our research was focused on the non-diapausing (ND) as well as the&nbsp;diapausing larvae&nbsp; (D) that&nbsp; were exposed to low temperatures during different phases&nbsp; of&nbsp;diapause.</p><p>During analysis of European corn borer&nbsp; <em>O. nubilalis</em>&nbsp; lipids, the following techniques was&nbsp;used: thin&nbsp; layer&nbsp; chromatography (TLC) with scanning densitometry, for the separation and&nbsp;quantification&nbsp; of lipid classes; gas-mass chromatography (GC-MS ) for the&nbsp; analysis of the&nbsp;fatty acid composition&nbsp; of lipids and&nbsp; the differential scanning calorimetry (DSC), for the&nbsp;thermal analysis of the extracted lipids.</p><p>The fatty acid compositions&nbsp; and biophysical properties of lipids differed markedly between&nbsp;non-diapausing and diapausing larvae&nbsp; of&nbsp; <em>O. nubilalis</em>. Diapause was associated with a&nbsp;dramatic increase&nbsp; mainly the proportions of palmitoleic acid (16:1n-7) and oleic acid (18:1n-9), with concurrent reductions in palmitic acid (16:0) and linoleic acid (18:2n-6). The increase&nbsp;in&nbsp; the level of unsaturation of&nbsp; lipids,&nbsp; which caused a marked shift in their phase transitions to&nbsp;lower temperatures,&nbsp; was triggered&nbsp; by diapause rather than low temperatures.&nbsp; Adjustments of&nbsp;fatty acid compositions are likely to be an important component of winter diapause &nbsp;mechaisms, possibly maintaining the fluidity of cell membranes, and the functionality &nbsp;of the&nbsp;organism during lower winter temperatures.&nbsp; We conclude that&nbsp; <em>O. nubilalis &nbsp;</em>undergoes&nbsp;remodeling of fatty acid profiles of lipids as an element of its overwintering physiology which&nbsp;may improve the ability to harden during diapause.</p>

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-10-06T19:48:50Z No. of bitstreams: 1 TeseRFP.pdf: 32637155 bytes, checksum: d3cc624aead32f85bad14acdb9612054 (MD5) / Approved for entry into archive by Ronildo Prado (producaointelectual.bco@ufscar.br) on 2017-10-10T19:37:58Z (GMT) No. of bitstreams: 1 TeseRFP.pdf: 32637155 bytes, checksum: d3cc624aead32f85bad14acdb9612054 (MD5) / Approved for entry into archive by Ronildo Prado (producaointelectual.bco@ufscar.br) on 2017-10-10T19:38:10Z (GMT) No. of bitstreams: 1 TeseRFP.pdf: 32637155 bytes, checksum: d3cc624aead32f85bad14acdb9612054 (MD5) / Made available in DSpace on 2017-10-10T19:42:50Z (GMT). No. of bitstreams: 1 TeseRFP.pdf: 32637155 bytes, checksum: d3cc624aead32f85bad14acdb9612054 (MD5) Previous issue date: 2017-06-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Ecological studies were carried out in twenty-five natural temporary aquatic environments, located in the cities of Urucuia, Lagoa Grande and Pirapora, in the north and northwest of the state of Minas Gerais, Brazil. In each environment, collections were carried out in April 2015, May 2016 and January 2017, during which limnological variables were measured and samples from the phytoplankton (qualitative) and zooplankton (qualitative and quantitative) communities, as well as from sediment, were collected. Experiments were also carried out in the laboratory to evaluate the effects of different temperatures and luminosity on the hatching of diapause eggs of zooplankton species present in these environments. In general, the values obtained for the physical and chemical variables of the studied environments were in a favorable range to the development of the phytoplankton community. However the low concentration of chlorophyll a and the low richness of phytoplankton species may be reflections of the low water transparency, and the turbidity may limit the growth of the phytoplankton. Qualitative and quantitative analyzes of the zooplankton community indicated low species richness in these ponds. Although Rotifera presented a greater richness of taxa, Copepoda Cyclopoida was the most abundant and numerically representative group. The presence or absence of the Anostraca Dendrocephalus brasiliensis does not seem to interfere in the composition and density of the zoplanktonic community. Species richness and local diversity should be related to disturbances and environmental dynamics. The results obtained in the experiment of hatching of zooplankton diapause eggs showed that the different ponds have similar hatching values, and low temperatures (20°C) and absence of light have a negative influence on hatching these eggs. In addition, it was observed that higher temperatures (35°C) accelerated the hatching of the diapause eggs during the first days of incubation. Thus we can infer that, in general, zooplankton community present in all the studied temporary aquatic environments behave in a similar way. / Foram realizados estudos ecológicos em vinte e cinco ambientes aquáticos temporários naturais, localizados nos municípios de Urucuia, Lagoa Grande e Pirapora, a norte e noroeste do estado de Minas Gerais, Brasil. Em cada ambiente, foram realizadas coletas em abril de 2015, maio de 2016 e janeiro de 2017, durante as quais foram medidas variáveis limnológicas e tomadas amostras das comunidades fitoplanctônica (qualitativas) e zooplanctônicas (qualitativas e quantitativas), além de amostras do sedimento. Também foram realizados experimentos em laboratório para avaliar os efeitos de diferentes temperaturas e da luminosidade sobre a eclosão de ovos de diapausa de espécies zooplanctônicas presentes nesses ambientes. De modo geral, os valores obtidos para as variáveis físicas e químicas dos ambientes estudados encontraram-se numa faixa favorável ao desenvolvimento da comunidade fitoplanctônica. No entanto, a baixa concentração de clorofila a e a baixa riqueza de espécies fitoplanctônicas podem ser reflexos da baixa transparência da água, sendo que a turbidez pode limitar o crescimento do fitoplâncton. Análises qualitativa e quantitativa da comunidade zooplanctônica indicaram baixa riqueza de espécies nessas lagoas. Embora o grupo Rotifera tenha apresentado maior riqueza de táxons, o grupo Copepoda Cyclopoida foi o mais abundante e representativo numericamente. A presença ou ausência do Anostraca Dendrocephalus brasiliensis parece não interferir na composição e na densidade da comunidade zooplanctônica, sendo que a riqueza de espécie e a diversidade local devem estar relacionadas a perturbações e dinâmica do ambiente. Os resultados obtidos no experimento de eclosão de ovos de diapausa do zooplâncton evidenciaram que as diferentes lagoas têm valores semelhantes de eclosão, sendo que baixas temperaturas (20°C) e ausência de luz têm influência negativa sobre a eclosão desses ovos. Além disso, foi observado que temperaturas mais elevadas (35°C) aceleraram a eclosão dos ovos de diapausa durante os primeiros dias de incubação. Assim, podemos inferir que, no geral, a comunidade zooplanctônica presente em todos os ambientes aquáticos temporários estudados se comporta de maneira semelhante. / CNPq: 141023/2013-9

Abstract The life histories of ectoparasites are shaped by both host and off-host environment. A suitable host is primarily needed during reproduction, whereas juvenile stages outside the host are directly exposed to environmental variability. Viviparity, i.e. the development of an embryo inside the body of the mother resulting in large offspring size, increases offspring survival. The production of large offspring has its consequences in terms of high variation in offspring age and in the environment that each young individual will face. I used a viviparous ectoparasite, the deer ked (Lipoptena cervi), to investigate the consequences of long reproductive lifespan and varying offspring environment on offspring life-histories and seasonal adaptations. Offspring life-histories varied seasonally. I showed that the resources provided by the deer ked females determine offspring performance throughout its off-host period. Offspring size increased towards the spring and the end of the reproductive period, and simultaneously offspring survival and cold tolerance increased. Seasonal variation in offspring size did not reflect the resources that would guarantee offspring survival during the longest diapause or the highest cold tolerance during the harshest winter period. Diapause intensity varies with birth time according to the expected length of the winter ahead. However, the deer ked pupae, regardless of their age, overwinter at an opportunistic diapause, which may be terminated rapidly only by an exposure to high temperature. Contrary to general observations, photoperiod has no role in regulating the seasonal shifts of the deer ked. Neither is high cold tolerance associated only with diapause, but it remains high through four seasons, also in the active developmental and adult stages. I also evaluated the effects of life-history variation on the invasion potential of the deer ked. I conducted a large-scale transplant experiment to test the survival and pupal development at and beyond the current range. I found that the lower spring and summer temperatures and the shorter growth season in the north cause a deterioration in pupal performance and shorten the flight period. However, the colder climate may not totally prevent further spread. A more important factor that will affect deer ked invasion is host availability, and especially in Finland, the density of the moose population. Seasonal variation in offspring life histories in viviparous ectoparasites differs from the variation patterns reported in most invertebrates. This may be due to the extremely large offspring size and to the fact that maternally derived resources determine offspring performance through the entire off-host period. Variation in offspring performance is thus determined by maternal resources and seasonal variation in the condition of the moose. / Tiivistelmä Useimpien ulkoloisten elinkierto on riippuvainen isännästä ja isännän ulkopuolella kasvavien jälkeläisten kohtaamista ympäristöoloista. Viviparia eli jälkeläisen kehitys naaraan sisällä ja siitä usein seuraava suuri jälkeläiskoko parantavat jälkeläisten selviytymistä. Suurten jälkeläisten tuottaminen pitkällä aikavälillä johtaa siihen, että eri-ikäiset jälkeläiset kohtaavat vuodenajasta riippuen hyvin erilaiset olosuhteet. Väitöstyössäni tarkastelin Suomessa nopeasti yleistyneen hirvieläinten ulkoloisen, hirvikärpäsen (Lipoptena cervi), avulla, mitä seurauksia viviparialla, pitkällä lisääntymiskaudella ja ympäristön vuodenaikaisvaihtelulla on jälkeläisten elinkierto-ominaisuuksiin. Väitöskirjatyössäni havaitsin, että hirvikärpäsjälkeläisten elinkiertopiirteet vaihtelevat jälkeläisen syntymäajan mukaan. Osoitin myös, että hirvikärpäsnaaraan jälkeläisilleen tarjoamat ravintovarat määrittelevät jälkeläisten isännästä riippumattoman elinkierron aikaisen menestyksen. Jälkeläisten keskimääräinen koko kasvoi lisääntymiskauden edetessä talvesta kohti kevättä, jolloin myös selviytyminen ja kylmänsietokyky paranivat. Jälkeläiskoon vuodenaikaisvaihtelu ei näin ollen vastaa jälkeläisten tarvitsemia resursseja suhteessa talvehtimisen pituuteen eikä korreloi koville talvipakkasille altistumisen todennäköisyyden kanssa. Lepotilan keston määrittelevä diapaussin syvyys vaihteli syntymävuodenaikaa vastaavasti. Diapaussin havaitsin kuitenkin olevan ensisijaisesti opportunistinen, jolloin pelkästään korkea lämpötila voi nopeasti päättää lepotilan kaikenikäisillä yksilöillä. Vastoin yleisiä käsityksiä valorytmi ei vaikuta diapaussin säätelyyn. Vastoin ennakko-odotuksia kylmänsietokyky säilyy korkeana vuoden ympäri ja kaikissa tutkituissa elinkierron vaiheissa. Sovelsin tutkimieni elinkiertopiirteiden vaikutusta myös lajin invaasiokykyyn, ja tutkin istutuskokeen avulla koteloiden selviytymistä ja kehitystä nykyisellä esiintymisalueella ja sen pohjoispuolella. Alhaisemmat kevät- ja kesälämpötilat sekä lyhyempi kasvukausi vähentävät aikuiseksi selviytymistä ja lyhentävät lentoaikaa syksyllä. Ilmastotekijöiden suhteen hirvikärpänen voisi esiintyä nykyistä pohjoisempana. Tärkein tekijä hirvikärpäsen leviämistä tarkasteltaessa on kuitenkin sopivien isäntäeläimien saatavuus ja Suomen oloissa erityisesti hirven eli hirvikärpäsen pääisännän kannan tiheys. Tutkimukseni perusteella ulkoloisten vivipariasta seuraava jälkeläisten elinkiertopiirteiden ajallinen vaihtelu eroaa muiden selkärangattomien vastaavasta vaihtelusta. Yhtenä syynä eroihin lienee se, että hirvikärpäsnaaras tuottaa erityisen suuria jälkeläisiä ja että jälkeläiset puolestaan ovat täysin riippuvaisia emon antamista resursseista. Emon lisääntymisresurssit ja hirven kunnon vuodenaikaisvaihtelu vaikuttavat mahdollisesti siihen, minkälaisia jälkeläisiä hirvikärpänen milloinkin kykenee tuottamaan.

Chionochloa, a genus of snow tussock grasses native to New Zealand, exhibits pronounced mast seeding. Chionochloa suffers very high levels of pre-dispersal flower and seed predation by three main insects: Eucalyptodiplosis chionochloae, a cecidomyiid midge, which is formally described here; Megacraspedus calamogonus, a gelechiid moth and Diplotoxa similis, a chloropid fly. Seven species of parasitoids that attack these seed predators were discovered. Four species parasitize M. calamogonus (one tachinid fly and three hymenopteran wasps), one parasitizes D. similis (Hymenoptera: Eulophidae) and two parasitize E. chionochloae, (a pteromalid wasp Gastrancistrus sp. and a platygastrid wasp Zelostemma chionochloae, which is given a formal description here). The abundance, predation levels by each of the insect species, and interactions between all the organisms in the community were studied across three elevations at Mount Hutt over three summer seasons. M. calamogonus was most abundant at 450 m altitude during all three seasons. D. similis was most common at 1070 m altitude, while its predation levels peaked in low flowering seasons and decreased in high seasons. E. chionochloae was abundant in all three altitudes and increased its predation levels with increasing flowering intensity. E. chionochloae was confirmed to use prolonged diapause of at least three years. Prolonged diapause was also confirmed in its two parasitoids. Chionochloa plants were manipulated with various treatments to test the effect on diapause in E. chionochloae and its two parasitoids. Treatments included plant warming, root pruning, gibberellic acid sprayed on the plants and combinations of these treatments. All three insects changed their emergence in response to some treatments and therefore it was suggested that combined with risk-spreading diapause, they may use some predicting to emerge from prolonged diapause. E. chionochloae control their diapause following some of the cues that Chionochloa use for flowering, while Z. chionochloae and Gastrancistrus in some cases follow their host’s cues and in others use similar cues as Chionochloa plants. Emergence or diapause predictions differed across elevations and plant species in all three insect seed/flower predators. E. chionochloae had female-biased sex ratios in different populations even after prolonged diapause. There was week evidence that both parasitoid species are female-biased in the first emergence year and male-biased after more than one year in diapause. Therefore it was suggested that diapause is not more costly for females of E. chionochloae and its parasitoid than for males. Females of all three species were not found to be better predictors (i.e, more likely to respond to treatments by not entering extended diapause) than males. The complex interactions of all the organisms in this web are thought to be sensitive to climate, and it was suggested that the global climate change may alter this sensitive system.

Chionochloa, a genus of snow tussock grasses native to New Zealand, exhibits pronounced mast seeding. Chionochloa suffers very high levels of pre-dispersal flower and seed predation by three main insects: Eucalyptodiplosis chionochloae, a cecidomyiid midge, which is formally described here; Megacraspedus calamogonus, a gelechiid moth and Diplotoxa similis, a chloropid fly. Seven species of parasitoids that attack these seed predators were discovered. Four species parasitize M. calamogonus (one tachinid fly and three hymenopteran wasps), one parasitizes D. similis (Hymenoptera: Eulophidae) and two parasitize E. chionochloae, (a pteromalid wasp Gastrancistrus sp. and a platygastrid wasp Zelostemma chionochloae, which is given a formal description here). The abundance, predation levels by each of the insect species, and interactions between all the organisms in the community were studied across three elevations at Mount Hutt over three summer seasons. M. calamogonus was most abundant at 450 m altitude during all three seasons. D. similis was most common at 1070 m altitude, while its predation levels peaked in low flowering seasons and decreased in high seasons. E. chionochloae was abundant in all three altitudes and increased its predation levels with increasing flowering intensity. E. chionochloae was confirmed to use prolonged diapause of at least three years. Prolonged diapause was also confirmed in its two parasitoids. Chionochloa plants were manipulated with various treatments to test the effect on diapause in E. chionochloae and its two parasitoids. Treatments included plant warming, root pruning, gibberellic acid sprayed on the plants and combinations of these treatments. All three insects changed their emergence in response to some treatments and therefore it was suggested that combined with risk-spreading diapause, they may use some predicting to emerge from prolonged diapause. E. chionochloae control their diapause following some of the cues that Chionochloa use for flowering, while Z. chionochloae and Gastrancistrus in some cases follow their host’s cues and in others use similar cues as Chionochloa plants. Emergence or diapause predictions differed across elevations and plant species in all three insect seed/flower predators. E. chionochloae had female-biased sex ratios in different populations even after prolonged diapause. There was week evidence that both parasitoid species are female-biased in the first emergence year and male-biased after more than one year in diapause. Therefore it was suggested that diapause is not more costly for females of E. chionochloae and its parasitoid than for males. Females of all three species were not found to be better predictors (i.e, more likely to respond to treatments by not entering extended diapause) than males. The complex interactions of all the organisms in this web are thought to be sensitive to climate, and it was suggested that the global climate change may alter this sensitive system.

Trade-off between reproduction and longevity is a widely accepted fact, yet proximate mechanisms are scarcely understood. In this work I tested differences in lifespan between diapause and non-diapause males of a model insect, the linden bug Pyrrhocoris apterus. Also the role of juvenile hormone in regulation of longevity and immunity (measured by relative phenoloxidase activity) was assessed. In addition to that, I examined if juvenile hormone is the mediator of reduction in longevity induced by mating.

A sister group of the Arthropoda, the Tardigrada are micrometazoans that occupy a diversity of niches in freshwater, marine, and terrestrial habitats. Commonly called water bears because of their slow, lumbering gait, these molting lobopods have four pairs of legs, usually terminating in claws. Most are less than 1 mm in length, with a complete digestive tract, a dorsal gonad with one or two gonoducts, and a dorsal lobed brain with a ventral nerve cord and four bilobed ganglia, one per leg-bearing metamere. The body cavity (hemocoel) functions in respiration and circulation. Over 1200 species have been described based primarily on the morphology of the claws and buccal-pharyngeal apparatus. Individuals may be either gonochoric, unisexual, or hermaphroditic, with fertilized or unfertilized eggs deposited either freely or within the shed exuvium. Parthenogenesis occurs frequently in limnic and terrestrial tardigrades, allowing them to colonize new territories by passive dispersal of a single individual. Cryptobiosis (anhydrobiosis, anoxybiosis, cryobiosis, and osmobiosis) and diapause (encystment and resting eggs) occur during the life history. Active adults (surrounded by water) and cryptobiotic adults and eggs are primarily dispersed passively, but some active dispersal can also occur. Due to the characteristic patchy distributions of tardigrade populations, little is known about their population dynamics and trophic relationships. Improved methods for collection, microscopy, culturing, and molecular analyses have been have contributed much to our knowledge of tardigrades.

科学研究費補助金 研究種目:特定領域研究(A)(1) 課題番号:08276103 研究代表者:山下 興亜 研究期間:1996-2000年度