Body temperature of the parasitic wasp Pimpla turionellae (Hymenoptera) during host location by vibrational sounding

Abstract.  The pupal parasitoid Pimpla turionellae (L.) uses self-produced vibrations transmitted on the plant substrate, so-called vibrational sounding, to locate immobile concealed pupal hosts. The wasps are able to use vibrational sounding reliably over a broad range of ambient temperatures and even show an increased signal frequency and intensity at low temperatures. The present study investigates how control of body temperature in the wasps by endothermic mechanisms may facilitate host location under changing thermal environments. Insect body temperature is measured with real-time IR thermography on plant-stem models at temperature treatments of 10, 18, 26 and 30 °C, whereas behaviour is recorded with respect to vibrational host location. The results reveal a low-level endothermy that likely interferes with vibrational sound production because it occurs only in nonsearching females. At the lowest temperature of 10 °C, the thoracic temperature is 1.15 °C warmer than the ambient surface temperature whereas, at the high temperatures of 26 and 30 ° C, the wasps cool down their thorax by 0.29 and 0.47 °C, respectively, and their head by 0.45 and 0.61 °C below ambient surface temperature. By contrast, regardless of ambient temperature, searching females always have a slightly elevated body temperature of at most 0.30 °C above the ambient surface temperature. Behavioural observations indicate that searching females interrupt host location more frequently at suboptimal temperatures, presumably due to the requirements of thermoregulation. It is assumed that both mechanisms, producing vibrations for host location and low-level endothermy, are located in the thorax. Endothermy by thoracic muscle work probably disturbs signal structure of vibrational sounding, so the processes cannot be used at the same time.     

Computational modeling and experimental validation of odor detection behaviors of classically conditioned parasitic wasp,Microplitis croceipes

A prototype chemical sensor named Wasp hound® that utilizes five classically conditioned parasitoid wasps, Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), to detect volatile odors was successfully implemented in a previous study. To improve the odor‐detecting ability of Wasp Hound®, searching behaviors of an individual wasp in a confined area are studied and modeled through stochastic differential equations in this paper. The wasps are conditioned to 20 mg of coffee when associated with food and subsequently, tested to 5, 10, 20, and 40 mg of coffee. A stochastic model is developed and validated based on three positive behavioral responses (walking, rotation around odor source, and self‐rotation) from conditioned wasps at four different test dosages. The model is capable to reproducing the behaviors of conditioned wasps, and can be used to improve the ability of Wasp Hound® to assess changes in odor concentration. The model simulation results show the behaviors of conditioned wasps are significantly different when tested at different coffee dosages. We conjecture that the searching behaviors of conditioned wasps are based on the temporal and spatial neuron activity of olfactory receptor neurons and glomeruli, which are strongly correlated to the training dosages. The overall results demonstrate the utility of mathematical models for interpreting experimental observations, gaining novel insights into the dynamic behavior of classically conditioned wasps, as well as broadening the practical uses of Wasp Hound. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:596–606, 2015     

Physiological determinants of Ficus fruit temperature and implications for survival of pollinator wasp species: comparative physiology through an energy budget approach

Figs are completely dependent for pollen dispersal on species-specific fig-pollinating wasps that develop within developing fig fruits. These wasps are very sensitive to heat and die at temperatures only a few degrees above ambient. Such temperatures are expected and observed in objects exposed to full sunlight, as fig fruits frequently are. In detailed field and experimental studies of 11 species of Panamanian figs with fruit ranging in size from 5 mm to 50 mm in diameter, we found that both the relative and absolute contribution of transpiration to maintaining non-lethal fruit temperatures increased with fruit size. Small and large fruits reached temperatures of 3 and 8°C, respectively, above air temperature in full sunlight when transpiration was prevented by grease. The temperature reached by large, nontranspiring fruits was sufficient to kill their pollinators. Control fruits which transpired reached temperatures of 2–3°C above air temperature in sunlight, regardless of size. An analysis of the solar energy budget of fruit revealed that large fruits must transpire to maintain tolerable temperatures for the wasps because heat diffusion from fruit to air was too low to balance net radiation in sunlight. By contrast, small fruits do not need to transpire to maintain tolerable temperatures for the pollinators.     

Vibration and sound communication in solitary bees and wasps

ABSTRACT. Females of solitary bees ( Colletes cunicularius L.) and of digger wasps ( Bembix rostrata L.) produce buzzing sounds and are known to secrete volatile odours when digging their way from the subterranean nests to the soil surface. The odours allow patrolling males to determine the approximate position of the digging virgin female. The buzzes are measured as substrate-borne sound (soil buzz vibrations) and as air-borne sound (soil buzz sounds). Play-back experiments suggest that the soil buzzes are used by the males as additional cues for localization. Faint buzz sounds are emitted regularly by the male during genital contact in copulation. They may serve to change the receptivity of the female. Intense and broadband buzz sounds are produced by bees of either sex, if restrained from moving, perhaps serving to deter predators.     

Ambient temperature affects mechanosensory host location in a parasitic wasp

Certain parasitic wasps (Ichneumonidae, Pimplinae) use self-produced vibrations transmitted on plant substrate to locate their immobile concealed hosts (i.e. lepidopteran pupae). This mechanosensory mechanism, called the vibrational sounding, depends both on physical cues of the environment and physical activity of the parasitoid and is postulated to depend on ambient temperature. We analysed the influences of temperature on vibrational sounding by choice experiments using plant-stem models with hidden host mimics in the temperate species Pimpla turionellae. The results show a significant effect of temperature on host-location activity and on the success of this process. Outside an optimum range, the performance of the wasps decreased both at low and high temperatures. Below 10°C and beyond 24°C, the wasps displayed (1) substantial reduction in responsiveness, i.e. proportion of females showing ovipositor insertions, (2) reduction of quantitative activity with ovipositor insertions in the individuals, and (3) reduced precision of mechanosensory host location. Nevertheless, female wasps were able to locate their host over a surprisingly broad range of ambient temperatures which indicates that the wasps are able to compensate for temperature effects on vibrational sounding.     

Effect of warm-up on the standing broad jump in trained and untrained men and women

The effect of 3 warm-up routines on standing broad jump (SBJ) performance was investigated. Thirty-two men and women participated as subjects. Following the determination of 1-repetition maximum (1RM) squat, subjects completed warm-up routines and broad jumps on 4 occasions in a randomized order. Subjects performed SBJ immediately (POST) and 15 min following (POST15) the given warm-up routine. The routines were high force, consisting of high % 1RM, low repetition squats; high power, consisting of low % 1RM, low repetition speed squats; stretching, consisting of static stretches; and no activity, a control condition. Repeated measures analysis of covariance (ANCOVA) revealed no differences among broad jump performance following any of the warm-up routines (p = 0.157). A strong correlation (R = 0.805) was found between 1RM squat and SBJ. These data indicate that warm-up of any type has little effect on jump performance and that maximum strength is strongly related to jumping ability.     

Thermoregulation in four species of tropical solitary bees: the roles of size,sex and altitude

Body temperatures during free flight in the field, warm-up rates during pre-flight warm-up, and temperatures during tethered flight are measured for four tropical solitary bee species at three sites of differing altitude in Papua New Guinea. All four species are capable of endothermic preflight warm-up; three species give slopes of thoracic temperature on ambient temperature of significantly less than 1, indicating regulation of thoracic temperature. In the kleptoparasitic Coelioxys spp. (Megachilidae) and Thyreus quadrimaculatus (Anthophoridae), warm-up rates and thoracic temperatures in flight are low by comparison with the two provisioning species Creightonella frontalis (Megachilidae) and Amegilla sapiens (Anthophoridae). In both C. frontalis and A. sapiens thoracic temperatures correlate positively and significantly with both ambient temperature and body mass. In A. sapiens, body mass increases with altitude; this can be interpreted as a response to lower ambient temperatures at higher altitude, an example of Bergmann's rule. In both A. sapiens and C. frontalis populations at higher altitude have higher thoracic temperatures independent of differences of body mass, suggestive of additional morphological or physiological adaptation to lower ambient temperatures. In A. sapiens there is no qualitative difference in body temperatures between males and females after controlling for body mass, while male C. frontalis have significantly lower thoracic temperatures than females of the species. This difference between A. sapiens and C. frontalis is discussed with reference to variation in mating systems found in the Apoidea.Abbreviations C.R.I. Christensen Research Institute - P.N.G. Papua New Guinea - SFT stable flight temperature - T _a ambient air temperature - T _ab abdominal temperature - T _dif the temperature difference between thorax and abdomen - T _ex thoracic temperature excess - VFT voluntary flight temperature     

宽瓣头细蛾形态及生物学特性研究

宽瓣头细蛾Epicephala lativalvaris Li, Wang & Zhang是最近发现在黑面神Breynia fruticosa和喙果黑面神B. rostrata上专性传粉的昆虫。通过野外观察宽瓣头细蛾的访花行为、 室内饲养宽瓣头细蛾幼虫及解剖黑面神和喙果黑面神果实, 首次对其个体发育过程中各虫态的形态特征及生活习性和生活史进行了详细研究。结果表明： 宽瓣头细蛾的生活史因气候的不同而出现差异, 其在福建厦门1年发生4~5代, 有4个羽化主要高峰期, 分别为5月上旬至中旬、 6月中旬至下旬、 8月及9月下旬至10月上旬, 11月中下旬有少数成虫羽化, 12月上旬至次年4月中旬以卵或蛹越冬; 而在海南鹦哥岭1年发生6代, 无越冬现象。成虫分别主动为黑面神或喙果黑面神传粉并将卵产于子房内, 幼虫以寄主植物种子为食, 需要消耗果实内全部6粒种子才能发育成熟, 但每个种群内留有20.37%~77.63%完好的果实, 以维持互利关系的稳定。两种植物的结实率近似, 但宽瓣头细蛾对喙果黑面神的果实危害率是黑面神的2.05倍。结果说明, 在宽瓣头细蛾 黑面神和喙果黑面神专性传粉互利共生关系中, 两种寄主植物所获得的利益近似, 但喙果黑面神为宽瓣头细蛾提供了更多的回报。研究结果为头细蛾属其他种类生物学特性的了解提供了借鉴, 并为探讨宽瓣头细蛾 黑面神和喙果黑面神专性传粉互利共生关系稳定性的维持机制提供了基本依据。     

Chemical and pharmacological investigations of Metaxya rostrata

In a bioassay-guided approach the chemical composition of rhizomes of Metaxya rostrata (Kunth C. Presl) was studied for the first time. Investigations of the cytotoxicity of extracts and fractions on SW480 colorectal carcinoma cells resulted in the isolation of two polyphenols--cinnamtannin B-1 and aesculitannin B. The structures of the compounds were elucidated by different NMR experiments. Additionally, sugars, common sterols, such as sitosterol, stigmasterol and campesterol, as well as chlorogenic acid and caffeic acid were identified in Metaxya rostrata.     

Dispersal of adult female fig wasps 1. Arrivals and departures

Ficus burtt-davyi, like most other fig species (Ficus, Moraceae), is exclusively pollinated by its own unique species of fig wasp, in this caseElisabethiella baijnathi (Chalcidoidea, Agaonidae). Because fig crop development on any one tree is usually synchronised, the small and short-lived female wasps have to migrate and find other trees bearing figs which are at suitable stage of development for oviposition. However, the likelihood of successful location and subsequent arrival at a new host tree is dependent on distance and the effect of environmental factors such as wind and temperature. This study examines the relationship between ambient temperatures and the timing of fig wasps emergence from their natal figs and the commencement of their dispersal flight. The behaviour of the wasps arriving at figs which were ready to be pollinated was also examined. The female wasps did not appear to distinguish between the figs and other parts of the tree when in flight. However, after landing on the tree their search for figs was more directed as they visited more figs than leaves. Short-range recognition of figs appears to be by contact chemo-reception, but the wasps showed a preference for entering figs which did not already contain a female wasp.     

Validation of a model for prediction of skin temperatures in footwear

A model for foot skin temperature prediction was evaluated on the basis of 2 experiments on subjects at various environmental temperatures (light seated manual work at -10.7 degrees C (Study 1), and a short walking period in combination with standing and sitting at +2.8 degrees C, -11.8 degrees C and -24.6 degrees C (Study 2), with boots of 3 insulation levels. Insulation of the footwear was measured on a thermal foot model. Predicted and measured data showed a relatively good correlation (r = 0.87) at the 2 colder conditions in Study 2. The environmental temperature of 2.8 degrees C was not low enough at the chosen activity for a considerable foot skin temperature drop. In Study 1 the predicted temperature stayed higher for the whole exposure period and the difference between the predicted and the measured foot skin temperatures grew proportionally with time, while subsequent warm-up curves at room temperature were almost parallel. In Study 1 the correlation was 0.95. However, the paired t-test showed usually significant differences between measured and predicted foot skin temperatures. The insulation values from thermal foot measurements can be used in the model calculations. Lotens' foot model is lacking activity as direct input parameter, however, the blood flow is used instead (effect through Tcore). The Lotens foot model can give reasonable foot skin temperature values if the model limitations are considered. Due to the lack of activity level input, it will be difficult to make any good estimation of foot skin temperature during intermittent exercise. The rate of the foot temperature recovery after cold exposure was somewhat overestimated in the model--the warm-up of the feet of the subjects started later and was slower in the beginning of the warm-up than in the prediction. It could be useful to develop the model further by taking into consideration various wetness and activity levels.     

Cadmium and copper uptake and accumulation by Sesbania rostrata seedling, a N-fixing annual plant: implications for the mechanism of heavy metal tolerance

Sesbania rostrata,an annual tropical legume,has been found to be tolerant to heavy metals,with an unknown mechanism.It is a promising candidate species for revegetation at mine tailings.In this study,sequential extractions with five buffers and strong acids were used to extract various chemical forms of cadmium and copper in S.rostrata,with or without Cd or Cu treatments,so that the mechanisms of tolerance and detoxification could be inferred.Both metals had low transition rates from roots to the aboveground of S.rostrata.The transition ratio of Cd (4.00%) was higher than that of Cu (1.46%).The proportion of NaCl extracted Cd (mostly in proteinbinding forms) increased drastically in Cd treated plants from being undetectable in untreated plants.This suggests that Cd induced biochemical processes producing proteinlike phytochelatins that served as a major mechanism for the high Cd tolerance of S.rostrata.The case for Cu was quite different,indicating that the mechanism for metal tolerance in S.rostrata is metal-specific.The proportion of water-insoluble Cu (e.g.oxalate and phosphate) in roots increased significantly with Cu treatment,which partially explains the tolerance of S.rostrata to Cu.However,how S.rostrata copes with the high biotic activity of inorganic salts of Cu,which increased in all parts of the plant under Cu stress,is a question for future studies.Sesbania rostrata is among the very few N-fixing plants tolerant to heavy metals.This study provides evidence for the detoxification mechanism of metals in Sesbania rostrata.     

Manipulation of parasitoid size using the temperature-size rule: fitness consequences

The phenotypic effects of rearing temperature on several fitness components of the koinobiont parasitoid, Aphidius colemani, were examined. Temperatures experienced during development induced a plastic linear response in the dry and fat masses of the immature stage and a non-linear response in the growth rate as well as in the size of adults. We investigated if the phenotypic morphometrical plasticity exhibited by parasitoids reared at different temperatures can induce variations in fitness-related traits in females. We did not find any difference in immature (pupal) mortality in accordance to rearing temperature. However, when examining adult longevity, we found an inverse linear relation with developmental temperature, confirming the usual rule that larger and fatter wasps live longer than smaller ones. The pattern of female fecundity was non-linear; wasps that developed at high and low temperatures were less productive. We suggest that when development is short, the accumulated reserves are not adequate to support both fecundity and survival. By manipulating adult size through changes in the rearing temperature, we showed that the usual shape of the size/fitness function is not always linear as expected. Developmental temperature induced a plasticity in energy reserves which affected the functional constraints between survival and reproduction.     

Effect of linear polarized near-infrared light irradiation and light exercise on muscle performance

This study aimed to determine the effect of active warm-up by local muscle light exercise and passive warm-up by polarized light irradiation on skin and muscle temperatures and forearm muscle performance (muscle strength, power, endurance, and controlled force-exertion). Ten healthy males performed various grip tests before and after active (local muscle light exercise) and passive (linear polarized near-infrared light irradiation) warm-ups. An active warm-up involved intermittent gripping exercise (contraction: 1 second and relaxation: 1 second) for 10 minutes using a sponge. A passive warm-up consisted of polarized light irradiation to the forearm (superficial digital flexor) for 10 minutes (irradiation: 5 seconds and rest: 1 second). Skin and muscle temperatures were measured during both warm-ups. Skin and muscle temperatures increased significantly after 5 minutes of local muscle light exercise and after 10 minutes of polarized light irradiation. Temperatures were significantly higher after 6 minutes of local muscle light exercise than after 6 minutes of polarized light irradiation. There were no significant differences of muscle strength, power, and controlled force-exertion before and after either warm-up. Average force outputs in all conditions significantly decreased with exertion time, and at 30, 60, 90, and 120 seconds they were higher in both warm-up conditions than in the non-warm-up condition. In conclusion, both warm-ups may contribute to improve muscle endurance performance in the decreasing force phase.     

Evolution of the suctorial proboscis in pollen wasps (Masarinae, Vespidae)

The morphology and functional anatomy of the mouthparts of pollen wasps (Masarinae, Hymenoptera) are examined by dissection, light microscopy and scanning electron microscopy, supplemented by field observations of flower visiting behavior. This paper focuses on the evolution of the long suctorial proboscis in pollen wasps, which is formed by the glossa, in context with nectar feeding from narrow and deep corolla of flowers. Morphological innovations are described for flower visiting insects, in particular for Masarinae, that are crucial for the production of a long proboscis such as the formation of a closed, air-tight food tube, specializations in the apical intake region, modification of the basal articulation of the glossa, and novel means of retraction, extension and storage of the elongated parts. A cladistic analysis provides a framework to reconstruct the general pathways of proboscis evolution in pollen wasps. The elongation of the proboscis in context with nectar and pollen feeding is discussed for aculeate Hymenoptera.     

Rhizobial factors required for stem nodule maturation and maintenance in Sesbania rostrata-Azorhizobium caulinodans ORS571 symbiosis

The molecular and physiological mechanisms behind the maturation and maintenance of N(2)-fixing nodules during development of symbiosis between rhizobia and legumes still remain unclear, although the early events of symbiosis are relatively well understood. Azorhizobium caulinodans ORS571 is a microsymbiont of the tropical legume Sesbania rostrata, forming N(2)-fixing nodules not only on the roots but also on the stems. In this study, 10,080 transposon-inserted mutants of A. caulinodans ORS571 were individually inoculated onto the stems of S. rostrata, and those mutants that induced ineffective stem nodules, as displayed by halted development at various stages, were selected. From repeated observations on stem nodulation, 108 Tn5 mutants were selected and categorized into seven nodulation types based on size and N(2) fixation activity. Tn5 insertions of some mutants were found in the well-known nodulation, nitrogen fixation, and symbiosis-related genes, such as nod, nif, and fix, respectively, lipopolysaccharide synthesis-related genes, C(4) metabolism-related genes, and so on. However, other genes have not been reported to have roles in legume-rhizobium symbiosis. The list of newly identified symbiosis-related genes will present clues to aid in understanding the maturation and maintenance mechanisms of nodules.     

Diversity in bee (Hymenoptera: Apoidea) and social wasp (Hymenoptera: Vespidae, Polistinae) community in "campos rupestres", Bahia, Brazil

Hymenoptera such as bees and social wasps are regular floral visitors in "campos rupestres" vegetation. A community of bees and social wasps was studied during floral visitation in an area of "campos rupestres", at Chapada Diamantina, BA, Brazil, from September 2001 to April 2002. The community was described in relation to diversity, evenness, and dominance rank, considering the individuals abundance (H' = 2.14/ J' = 0.55) and biomass (H' = 2.34/ J' = 0.60). Thirty nine bee (588 individuals/ 15.742 g) and 11 social wasp species (52 individuals/ 2.156 g) were collected, being the first report of social wasps for the Brazilian "campos rupestres". The main species regarding number of individuals were Trigona spinipes (Fabricius), Apis mellifera L., Frieseomelitta francoi (Moure), and Bombus brevivillus Franklin. About 48% of the species were represented by a single individual. There was an inversion in the dominance rank when the species biomass was considered. B. brevivillus, A. mellifera, T spinipes, and other species represented by 15 individuals or less, such as the social wasps Synoeca cyanea (Olivier), Polistes canadensis (L.) and Myschocyttarus drewseni (Saussure), and the bees Eufriesea nigrohirta (Friese), Xylocopa grisescens Lepeletier and Megachile (Pseudocentron) sp.l were the predominant species. The use of biomass in diversity analysis permitted to detect differences in the relative contribution of species in hierarchy dominance. The comparison between bee faunas from different areas indicates a large similarity of the sampled fauna in Palmeiras (Bahia State) with neighboring ecosystems, although with low values of similarity.     

Behaviour of a specialist parasitoid, Cotesia melitaearum: from individual behaviour to metapopulation processes

Abstract. 1. Foraging behaviour and movement within and among host patches of the specialist parasitoid wasp Cotesia melitaearum (Braconidae) attacking the larvae of Melitaea cinxia (Nymphalidae) were studied in the field and in the laboratory.
2. In the field, female wasps aggregated in large host groups in the autumn and caused positive spatial density-dependent parasitism in the field. Wasps stayed longer with groups of pre-diapause caterpillars than with post-diapause caterpillars, but attacked them less frequently.
3. In the laboratory, wasps attacked larger larvae more readily than smaller larvae. Also in the laboratory, wasps exposed to larvae outside their protective webs showed differences in the rates at which they attacked larvae fed different diets, implicating host plant-derived chemicals as proximate cues for foraging wasps.
4. Mark–recapture studies indicated that there was a low rate of successful movement of wasps among groups of young larvae within a habitat patch in the autumn and no successful movement of wasps across non-habitat. In contrast, wasps moved frequently among groups of late-instar caterpillars in the spring.
5. Host caterpillars of different ages responded very differently to wasp attacks. Pre-diapause larvae remained in groups and used collective head-jerking behaviour to defend themselves, whereas post-diapause larvae dispersed away from the group immediately after being attacked.
6. Population and metapopulation level dynamics of the host–parasitoid interaction are discussed in light of these observations of the behaviour of individual wasps.     

Specialized pollination in the African milkweed Xysmalobium orbiculare: a key role for floral scent in the attraction of spider-hunting wasps

Specialized pollination by prey-hunting wasps is poorly documented in rewarding plants. Furthermore, the mechanisms of achieving specialization are not clear since flowers typically produce exposed nectar and have no morphological adaptations (such as long spurs) to exclude non-pollinating visitors. We investigated the pollination of Xysmalobium orbiculare and explored the functional roles of floral scent and nectar in attracting pollinators and deterring nectar robbers. Floral visitor observations showed that this milkweed is visited almost exclusively by pompilid wasps in the genus Hemipepsis. These wasps were the only insects to carry pollinia, and a cage experiment confirmed their effectiveness in removing and inserting pollinia on flowers. Hand-pollinations showed that plants are genetically self-incompatible and thus reliant on pollinators for seed set. Palatability experiments with honeybees showed that nectar is distasteful to non-pollinating insects and is therefore likely to play a functional role in deterring nectar thieves. Choice experiments in the field showed that the wasp pollinators are attracted primarily by floral scent rather than visual cues. Analysis of spectral reflectance of flowers revealed that flowers are dull colored and are unlikely to stand out from the background vegetation. We conclude that X. orbiculare is specialized for pollination by spider-hunting wasps in the genus Hemipepsis and utilizes floral scent to selectively attract its pollinators and unpalatable nectar to deter non-pollinating visitors.