核型多角体病毒感染对棉铃虫幼虫同类相残行为的影响

在室内研究核型多角体病毒（HaSNPV）感染对棉铃虫Helicoverpa armigera（Htibner）幼虫同类相残行为的影响。结果显示：感病棉铃虫随感病程度的加重,越容易被健康棉铃虫残食,而自然死亡的感病棉铃虫、冻死的感病棉铃虫和冻死的健康棉铃虫三者被健康棉铃虫残食的百分率无显著差异。表明感病棉铃虫和病虫尸体更易于被健康棉铃虫残食,是由于棉铃虫体力减弱而失去反击能力,不是由于病毒本身的影响。以健康棉铃虫、感病棉铃虫为残食者,冻死的病虫为被残食者,相残率无显著差异,表明病毒并未改变棉铃虫残食同类的天性。残食病虫的健康棉铃虫的化蛹率和羽化率均低于正常的健康棉铃虫,残食者为相残行为付出了很高的代价。     

高效液相色谱法检测菜蛾绒茧蜂幼虫体内多杀菌素残留

应用高效液相色谱法检测施用于寄主幼虫的多杀菌素可否传递到在其体内发育的寄生蜂幼虫。以对多杀菌素高抗的小菜蛾Plutella xylostella幼虫作为菜蛾绒茧蜂Cotesia plutellae的寄主,待绒茧蜂发育到1龄幼虫时,将浓度为50 mg/L的多杀菌素点滴到寄主幼虫背板上,随后让寄主幼虫取食经50 mg/L多杀菌素处理过的甘蓝叶片,寄主幼虫和其体内的蜂幼虫再发育3天后,将寄主幼虫解剖取出蜂幼虫,用高效液相色谱法对经多杀菌素处理的小菜蛾幼虫体液以及绒茧蜂幼虫匀浆液进行检测,结果多杀菌素的2个活性成分spinosyn A和spinosyn D均被检测到,两者的多杀菌素残留浓度分别是2.79 mg/L和0.94 mg/L。这表明,通过寄主幼虫体壁接触和取食进入其体内的多杀菌素,可通过寄生蜂幼虫体壁浸透、蜂幼虫对寄主血淋巴的取食,或这两种途经一起进入蜂幼虫的体内,对蜂幼虫产生作用。     

Effects of spatio-temporal intervals between newly-hatched larvae on larval survival and development inMonochamus alternatus (Coleoptera: Cerambycidae)

The effects of distance between hatching larvae on survival and development were investigated inMonochamus alternatus. Two newly-hatched larvae were inoculated intoPinus densiflora bolts at a distance of 2.5 cm or 10 cm, simultaneously or at an interval of 2 weeks. Some larvae were inoculated singly as a control. When larvae were inoculated simultaneously, mortality of the closely-inoculated larvae was significantly higher than that of distantly-inoculated larvae. Such high mortality was identified as due to conspecific bites. When the two larvae were inoculated asynchronously, the first-inoculated larvae killed some second-inoculated larvae but were never killed by them. Consequently, mortality was higher in second-inoculated larvae than in first-inoculated larvae. In particular, there was a significant difference in mortality between them when the larvae had been inoculated closely. The mortality of second-inoculated larvae was higher in the closely-inoculated group than in the distantly-inoculated group although there was no significant difference between them. In the case of two simultaneously-inoculated larvae, the initial distance between them had no significant effect on the development and growth in the early larval stage. When the larvae were inoculated asynchronously, the first-inoculated larvae grew more quickly than singly-inoculated control larvae.     

草地螟滞育幼虫的蛋白和核酸含量变化

为了阐明草地螟Loxostege sticticalis 滞育的分子调控基础, 本研究应用Trizol法、 DNA和蛋白质定量试剂盒、 SDS-PAGE电泳技术分别对进入滞育1, 2, 3和4个月、 解除滞育以及非滞育草地螟老熟幼虫中的核酸含量、 总蛋白含量和组分的变化进行了测定。结果表明： 滞育不同月份幼虫的总RNA含量显著低于非滞育幼虫的总RNA含量（P＜0.05）; 解除滞育幼虫的总RNA含量显著高于滞育2, 3和4个月的幼虫, 但仍显著低于非滞育的对照组。滞育不同月份、 非滞育以及解除滞育幼虫的总DNA含量没有显著差异（P＞0.05）。RNA/DNA比值随滞育的开始而显著下降, 随着滞育的结束而显著上升。滞育不同月份的幼虫总蛋白含量显著高于非滞育幼虫的总蛋白含量（P<0.05）, 但解除滞育与非滞育幼虫的总蛋白含量无显著差异。利用SDS-PAGE电泳分析发现滞育幼虫体内存在滞育关联蛋白, 蛋白条带在24 kDa左右, 但非滞育和已经解除滞育的幼虫则没有该蛋白条带。这些结果表明, 总RNA含量的降低、 RNA/DNA比值下降、 总蛋白含量的升高, 以及24 kDa蛋白的存在是草地螟幼虫滞育的主要生理特征。     

Larval competition for food between wild and hatchery-reared ayu, Plecoglossm altivelis Temminck et Schlegel, in culture ponds

To examine the larval competition between wild and hatchery ayu in the culture ponds, mixed rearing of 580 000 wild and 520 000 hatchery larvae was carried out in two 25-m³ ponds for 3 months, in contrast to the control in which 860 000 wild larvae were reared in another pond.
The number of wild larvae in the mixed-rearing treatments decreased rapidly 20 days after the start of mixed rearing, in contrast to hatchery larvae. Mortality of wild larvae was almost 100% at the end of the experiment (3 months), while the hatchery larvae showed the usual survival rate of 15–16%. In the control pond, however, 16% of the wild larvae survived. The wild larvae grew much slower (0.10mmday ^-1) than the hatchery larvae (0·26 mm day ^-1) in the mixed-rearing ponds, whereas the wild larvae in the control pond showed almost the same growth rate (0·24 mm day ^-1) as hatchery larvae. On day 6 the gut fullness of wild larvae was only 30% of that of the hatchery larvae in the mixed-rearing experiments. On day 46 the wild larvae occurred deeper in the mixed-rearing ponds than the hatchery larvae. This depth difference in vertical distribution appeared to cause a disadvantage for the wild larvae in the competition with hatchery larvae, since the food was supplied at the surface. Thus, the wild larvae starved and died.     

Cocoon-spinning larvae of Oriental fruit moth and Indianmeal moth do not produce aggregation pheromone

1 Mature larvae of the Oriental fruit moth (OFM) Grapholita molesta (Lepidoptera: Tortricidae) and the Indianmeal moth (IMM) Plodia interpunctella (Lepidoptera: Pyralidae) leave their food source in search of suitable pupation sites in which to spin cocoons. These sites are typically well-concealed cracks and crevices within the environment. Such cocooning behaviour is also observed in larvae of the codling moth (CM) Cydia pomonella (Lepidoptera: Tortricidae), which aggregate prior to pupation in response to a pheromone blend produced by cocoon-spinning conspecific larvae.
2 In laboratory experiments, we tested whether cocoon-spinning OFM and IMM larvae produce aggregation pheromones and whether CM larvae are cross-attracted to closely-related OFM larvae.
3 Fifth-instar OFM and IMM larvae were not attracted to, or arrested by, cocoon-spinning conspecifics. Moreover, fifth-instar CM larvae were not cross-attracted to either cocoon-spinning OFM or IMM larvae.
4 Analyses of volatiles released from cocoon-spinning OFM and IMM larvae revealed that both OFM and IMM lack components that are present in the aggregation pheromone of CM larvae. This information may help explain why CM larvae are not cross-attracted to cocooning OFM or IMM larvae.     

Direct and indirect effects of predatory wasps (Polistes sp.: Vespidae) on gregarious caterpillars (Hemileuca lucina: Saturniidae)

Summary We examined how predation by vespid wasps,Polistes dominulus andP. fuscatus, affected the behavior, growth rate and survivorship of aggregated caterpillars ofHemileuca lucina (Saturniidae). Although these larvae can exhibit a variety of defense and escape behaviors, in general larvae reacted to wasp attacks by clinging to the hostplant. Neighboring larvae in the aggregation responded by leaving the feeding site and moving to the interior or base of the plant. To determine wheter wasp attack affected the behavior and growth of the caterpillars that escaped, a field experiment was conducted with treatments of: 1) larvae exposed to wasps, 2) larvae protected from wasps, and 3) larvae protected from wasps but with the attack of wasps simulated (=harassment). Over just one instar, protected larvae gained significantly more weight than the harassed larvae, which in turn weighed significantly more than the larvae that escaped the wasps. The behavior of attacked and harassed larvae differed from that of the protected larvae; the disturbed larvae often fed in smaller groups and in shaded portions of the plant where only mature leaves were available. A laboratory experiment showed that at 35° C (daytime temperature) larvae had significantly higher relative growth rates and significantly shorter instar duration than larvae reared at 25° C. Our results suggest that wasps, in addition to killing caterpillars, indirectly affect larval fitness by slowing larval growth, at least in part by forcing larvae into cooler microhabitats where leaves are of lower quality.     

Physiological changes leading to anhydrobiosis improve radiation tolerance in Polypedilum vanderplanki larvae

High tolerance against various extreme environments exhibited by some anhydrobionts might be due to being almost completely desiccated, a state where little or no chemical reactions occur. We have shown that anhydrobiotic larvae of Polypedilum vanderplanki have higher tolerance against both high- and low-linear energy transfer (LET) radiation than hydrated larvae. It is of great interest to know how the desiccating larvae gain radiation tolerance. We therefore examined effects of high-LET radiation on four kinds of larvae: (1) normal hydrated (intact) larva, (2) intermediates between the anhydrobiotic and normal hydrated state, (3) almost completely dehydrated (anhydrobiotic) larvae, and (4) immediately rehydrated larvae that are assumed to have a similar molecular profile to anhydrobiotic larvae. The intermediates and immediately rehydrated larvae survived longer after high-LET radiation than intact larvae, indicating that radiation tolerance could be enhanced even in hydrated larvae. Physiological changes toward anhydrobiosis, e.g. accumulation of protectants or increasing damage repair capacity, correlate with improved radiation tolerance in hydrated larvae. In addition, almost complete desiccation further enhanced radiation tolerance, possibly in a different way from the hydrated larvae.     

Larviposition in the ovoviviparous blowfly Calliphora dubia

This study examined larviposition in Calliphora dubia Macquart (Diptera: Calliphoridae), an ovoviviparous blowfly of considerable forensic importance in Australia. Females in the field carried 22–83 live larvae, exhibiting a strong linear relationship between female size and the number of live larvae carried. Females took just over 1 min (mean 67.7 ± 7.7 s, n = 54) to larviposit live larvae on or near fresh liver in the laboratory. Females laid larvae at a mean rate of 1.2 ± 0.1 larvae/s, with the fastest rate being 3.4 larvae/s. Most females (70%) laid live larvae only, but 14% laid larvae and eggs at the same time and 16% laid eggs only (none of the eggs laid were viable). Females laying only live larvae laid a mean of 53.7 ± 2.3 larvae, whereas those laying only eggs laid a mean of 48.6 ± 2.8 eggs on each occasion. None of the eggs laid were viable. Most females (86%) laid all their larvae in a single spot, even if they engaged in several bouts of laying live larvae. Nearly one‐third of females did not lay all the live larvae in their ovisacs, but retained half of their complement of developed larvae. Females may be opting to spread their larvae across several carcasses in order to increase their survival and not to overcrowd small, ephemeral carcasses. The fact that a blowfly can lay either eggs or live larvae has enormous implications for the accurate determination of the post‐mortem interval (PMI) as the presence of larvae derived from eggs laid on the body add 6–18 h to the PMI. This paper represents the first report of the ability of female calliphorids to resorb some of their own live larvae.     

Queens of the Paper Wasp Polistes fuscatus (Hymenoptera: Vespidae) Discriminate among Larvae on the Basis of Relatedness

The ability of queens of the paper wasp Polistes fuscatus to recognize larvae on the basis of colony origin was investigated in the laboratory. In a blind, binary choice paradigm, queens discriminated between larvae from their own colony and unrelated larvae, and between larvae from a sister colony and unrelated larvae. However, queens failed to discriminate between larvae from their own colony and larvae from a sister colony, indicating that queens of multiple-foundress colonies may lack the ability to make intracolonial brood discriminations on the basis of relatedness. These results demonstrate that recognition of larvae is mediated by larval-borne, genetically specified odors. Gas chromatograph/mass spectral analysis revealed that adults and larvae have similar cuticular hydrocarbon profiles, suggesting that the cues mediating larval and adult recognition may be the same.     

Attraction to and learning from social cues in fruitfly larvae

We examined the use of social information in fruitfly larvae, which represent an ideal model system owing to their robust learning abilities, small number of neurons and well-studied neurogenetics. Focal larvae showed attraction to the distinct odour emanating from food occupied by other larvae. In controlled learning experiments, focal larvae preferred novel odours previously paired with food occupied by other larvae over novel odours previously paired with unoccupied food. When we gave groups of larvae a choice between food patches differing in quality, more larvae aggregated on the higher-quality food, suggesting that attraction to and learning about cues associated with other larvae can be beneficial. Furthermore, larvae were more likely to find the best available food patch in trials when that food patch was occupied by other larvae than in trials when that food patch was unoccupied. Our data suggest, however, that the benefits from joining others may be at least partially offset by the fitness costs of increased competition, because larvae reared in isolation did as well as or better than larvae reared in groups on three key fitness parameters: developmental rate, survival rate and adult dry body mass. Our work establishes fruitfly larvae as a highly tractable model species for further research on the mechanisms that modulate behaviour and learning in a social context.     

Differentiation of Paenibacillus larvae subsp. larvae,the cause of American foulbrood of honeybees,by using PCR and restriction fragment analysis of genes encoding 16S rRNA

A rapid procedure for the identification of Paenibacillus larvae subsp. larvae, the causal agent of American foulbrood (AFB) disease of honeybees (Apis mellifera L.), based on PCR and restriction fragment analysis of the 16S rRNA genes (rDNA) is described. Eighty-six bacterial strains belonging to 39 species of the genera Paenibacillus, Bacillus, Brevibacillus, and Virgibacillus were characterized. Amplified rDNA was digested with seven restriction endonucleases. The combined data from restriction analysis enabled us to distinguish 35 profiles. Cluster analysis revealed that P. larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens formed a group with about 90% similarity; however, the P. larvae subsp. larvae restriction fragment length polymorphism pattern produced by endonuclease HaeIII was found to be unique and distinguishable among other closely related bacteria. This pattern was associated with DNA extracted directly from honeybee brood samples showing positive AFB clinical signs that yielded the restriction profile characteristic of P. larvae subsp. larvae, while no amplification product was obtained from healthy larvae. The method described here is particularly useful because of the short time required to carry it out and because it allows the differentiation of P. larvae subsp. larvae-infected larvae from all other species found in apiarian sources.     

Dispersal of first-instar gypsy moth larvae in relation to population quality

Summary Field studies of dispersal by first instar gypsy moth larvae indicate that almost all larvae undergo an initial dispersal episode. However, in laboratory studies large larvae (from large eggs) disperse more frequently than small larvae (from small eggs) in the presence of favored food. Large larvae may be better adapted for dispersal. When larvae encounter unacceptable food or are denied food, larvae disperse more frequently and dispersal by small larvae is nearly as frequent as dispersal by large larvae. Factors affecting egg size may contribute to shifts in dispersal patterns of gypsy moth larvae and distribution of populations.Paper No. 2041, Massachusetts Agricultural Experiment Station, University of Massachusetts at Amherst. This research supported (in part) from Experiment Station Project No. 355     

Setting tools for the early assessment of the quality of thawed Pacific oyster (Crassostrea gigas) D-larvae

Parameters used to assess the survival of larvae after cryopreservation generally misestimate the damages that prevent larval development. The objectives of the present study were to 1) define the reliability of the survival rate, assessed at 2 and 7 days post fertilization, to estimate Pacific oyster larval quality after thawing, and 2) select complementary tools allowing an early and reliable estimation of their quality. Oyster larvae were reared for 25 h after fertilization at 19 °C and cryopreserved at early D-stage. Then, thawed larvae were incubated in 2-L beakers. At 2 days post fertilization, the survival rate of thawed Pacific oyster larvae was lower than that of fresh larvae for only one experiment (Experiment 3) among the four identical experiments carried out in this work (Experiments 1-4). By contrast, the survival of thawed larvae, as assessed 7 days after fertilization, was lower than that of fresh larvae for the four experiments. These results confirm that the quality of thawed larvae is lower than that of fresh larvae and that the survival rate, estimated 2 days post fertilization, is not adapted to a reliable estimation of the subsequent development ability of thawed larvae. Then, complementary parameters were tested at 2 days: the movement characteristics (Experiments 1 and 2) and the morphologic features (Experiments 3 and 4) of thawed larvae. Compared to values observed on fresh larvae, the percentage of thawed motile larvae was different for only one experiment (Experiment 2) of the two. Compared to control, a reduced Average Path Velocity (VAP) of larvae (determined at the D-larval stage using a CASA-Computer Assisted Sperm Analysis-system) was observed after thawing for both experiments (Experiments 1 and 2), suggesting the ability of larval movement velocity to assess the decrease of the quality of thawed oyster larvae. Using an ASMA (Automated Sperm Morphology Analysis) device, a lower area of thawed larvae was observed, compared to control and for the two experiments (Experiments 3 and 4). By contrast, the Crofton perimeter of thawed larvae was lower than that of control larvae for only one experiment (Experiment 3) and no significant difference of circularity between fresh and thawed larvae was recorded for Experiments 3 and 4. In conclusion, changes in the movement velocity (assessed by CASA) and in the area (measured by ASMA) of D-larvae allow an early and reliable estimation of the quality of thawed Pacific oyster larvae.     

Seasonal susceptibility of 'Bartlett' pears to codling moth (Lepidoptera: Tortricidae) infestation and notes on diapause induction

Seasonal susceptibility of 'Bartlett' pear, Pyrus communis L., to codling moth, Cydia pomonella (L.), infestation, successful completion of larval development after infestation, and the induction of C. pomonella diapause was studied from 1992 through 1995. The seasonal variation in C. pomonella infestation and larval survival were effected by changes in fruit maturity. In late May through mid-June, pears were hard and were not as successfully infested by C. pomonella and produced less larvae compared with fruit later in the season. In late June to mid-July, pears became more suitable for infestation and a greater percentage of the larvae completed their development. In late July through mid-August, pears were susceptible to infestation, but the larvae were less likely to successfully complete development than in the late June to mid-July period due to pear tissue breakdown. From mid-August through September, pears are unsuitable for infestation, and few larvae were produced. When fruit were infested with neonate larvae in late May and mature larvae emerged from the fruit in July, a low percentage of the larvae entered diapause. However, when fruit were infested with neonate larvae in early July and mature larvae emerged from the fruit in early August, the majority of the larvae entered diapause. When fruit were infested with neonate larvae in late July through September and mature larvae emerged from the fruit after mid-August, nearly all C. pomonella larvae had entered diapause.     

The possible contribution of pituitary hormones to the heterochronic development of gonads and external morphology in overwintered larvae of Hynobius retardatus.

In Hynobius retardatus, most larvae in regions of low elevation metamorphose by autumn of the same year. However, larvae of some populations found in cold, mountainous ponds cannot metamorphose within the year and become aged, overwintered larvae. Gonadal development in larvae under the age of 1 year (larvae developed from eggs spawned in the same year) and in aged, overwintered larvae (spawned and hatched in previous years) was examined at the same developmental stage (stage 63, full-grown larval stage). The number of germ cells and the cross-sectional areas of the gonads were much larger in 2-season-overwintered (third year) larvae than in larvae under the age of 1 year.To obtain reliable probes for investigating the possible contribution of TSH, FSH and LH to metamorphosis and gonadal development, cDNAs for Hynobius TSHbeta, FSHbeta and LHbeta genes were cloned. Their expressions were analyzed by means of semi-quantitative RT-PCR in larvae under the age of 1 year and in 2-season-overwintered larvae. No differences were observed in expression levels of either TSHbeta or LHbeta between larvae under the age of 1 year and the overwintered larvae. In contrast, expression of FSHbeta was much higher in the overwintered larvae than in larvae under the age of 1 year. These results suggest that gonadal development proceeds gradually with age even in the overwintered larvae, but that metamorphosis is retarded, probably due to the larvae's cold habitat. Heterochronic development of gonads and external morphology has been demonstrated in H. retardatus, suggesting a potency for neotenic reproduction in this species.     

Host recognition by the specialist endoparasitoidMicroplitis croceipes (Hymenoptera: Braconidae): Role of host- and plant-related volatiles

The specialist parasitoidMicroplitis croceipes Cresson can parasitize only noctuid larvae in the generaHelicoverpa andHeliothis. To be successful in their search for hosts, the ability to distinguish hosts from nonhosts feeding on the same plant is beneficial. In flight tunnel experiments, we found that prior to landing on the odor sourceM. croceipes were able to distinguish volatiles released from frass of host larvae(Helicoverpa zea Boddie) and nonhost larvae (Spodoptera exigua Hübner andSpodoptera frugiperda J. E. Smith) fed on cotton. However, an initial contact experience with frass of cotton-fed host larvae appeared to be critical for this ability. Wasps that had antennated frass of host larvae fed pinto bean diet were equally attracted to frass of host and nonhost larvae fed on pinto bean diet. In short-range walking experiments, wasps located cotton-fed host larvae faster than diet-fed larvae, regardless of their experience. Wasps that had antennated frass of cotton-fed host larvae were less attracted to cotton-fed nonhost larvae, compared to host larvae, and preferred to sting host larvae. Plant-related volatiles in host frass and larvae appear to play a major role in the successful location of host larvae.     

入侵早期食蚊鱼仔幼鱼食物组成、摄食策略及营养状况分析

饥饿是影响鱼类仔鱼早期存活的关键因素,入侵鱼类仔鱼耐饥饿能力对其种群增长与扩散意义重大。本文对滇池流域食蚊鱼Gambusia affinis奠基种群仔幼鱼摄食及仔鱼营养状况进行深入分析,初步了解了饥饿因素在食蚊鱼入侵早期种群增长中的影响。研究结果显示,该种群食蚊鱼仔幼鱼主要以枝角类、桡足类为食物,同时能够广泛利用栖息地食物资源,包括种类较为丰富的水生昆虫幼体、弹跳虫等,具有广食性的摄食策略,许多个体食物多样性指数>1。这些特点与其口裂较大、发育较为完善的特点密切相关。尽管如此,仍有高达73.27%的食蚊鱼仔鱼存在饥饿胁迫问题,可能与奠基种群自身生物学特点、仔鱼群体内部竞争、行为特点及环境资源差异化分布格局等因素密切相关。对奠基种群而言,入侵早期仔幼鱼面临陌生的栖息地生境,其摄食与营养状况对种群的定殖有关键影响。     

Age-dependent physiological responses of last instarHelicoverpa zea larvae to oral and topical application of precocene II

Newly-ecdysed last instar larvae ofH. zea grouped into 100-, 200-, 300-, or 400-mg categories were fed diet containing precocene II or given precocene II topically on the abdomen. The time for larvae to reach a maximal weight, time to pupation, growth rate, and the amount of precocene II excreted were calculated. Younger larvae of lower weights, which were fed or topically treated with precocene II required more time to reach their maximal weight, had a lower maximal weight, a lower growth rate, and required more time to pupate than control larvae. Older larvae represented by the largest weight category were less sensitive to precocene II, had a shorter delay in reaching maximal weight, and a shorter delay in the time to pupation than control larvae; larvae in the largest weight category that were fed precocene II also had smaller decreases in the growth rate. Growth rate declines for larvae given topical doses of precocene II, however, were largest for the oldest larvae. All larvae given a single topical dose excreted precocene II for several days and were most efficient at eliminating smaller doses; larger, older larvae excreted more precocene II than smaller, younger larvae. Age-dependent responses to precocene II indicate that growth and metabolic processes, as well as xenobiotic metabolism, change in last instar larvae.     

Ontogenetic- and condition-related effects of starvation on responsiveness in herring larvae (Clupea harengus L.) during repeated attacks by a model predator

The escape behaviour of fed and food-deprived herring larvae (20-30 mm SL) was studied during repeated attacks with a glass probe in order to investigate the causal mechanisms of starvation-induced changes in reaction to predators. Two experiments were set up: one where the fed and starved larvae were of the same age but of different sizes and one with groups of similar size but different ages. Biochemical and morphological condition measures described the condition of individual larvae. Starved larvae showed a lower responsiveness than fed larger larvae of the same age, and the responsiveness in this experiment decreased with decreasing nutritional status of the larvae. However, starved larvae that were of the same size but older than fed larvae showed a higher responsiveness, which could be explained by differences in development of sensory systems. A combination of condition and developmental factors thus explained the differences between starved and fed larvae. Both starved and fed larvae showed decreasing responsiveness over time with repeated attacks with no difference between starved and fed larvae in the relative change over time. The results emphasise the importance of taking into account individual age and/or development when the nutritional condition of wild-caught larvae is incorporated in survival models.