Predation byOligotricha striata caddis larvae on amphibian eggs: Effects of a high quality food on growth rate

In the field and also in the laboratoryOligotricha striata trichopteran larvae were observed to feed onRana temporaria eggs. Laboratory experiments revealed thatO. striata larvae preferred amphibian eggs to plant matter. The jelly-like sheath of the eggs was easily penetrated. A larva consumed 1 to 2 eggs per day. The supply of high quality food in the form of amphibian eggs was found to accelerate the growth ofO. striata larvae.     

蜂王幼虫与工蜂幼虫发育期食物消耗量的研究

以意大利蜜蜂Apis mellifera ligustica雌性幼虫为试验材料,用鲜王浆、葡萄糖、果糖和酵母抽提物分别配制不同日龄的蜂王幼虫食物和工蜂幼虫食物,采用室内人工饲养蜜蜂幼虫技术饲养12h以内的蜂王幼虫和工蜂幼虫,直到幼虫出现排便和吐丝行为,记录幼虫生长发育期间消耗的总食物量。结果表明:1只蜂王幼虫在生长发育期平均消耗196.8mg蜂王幼虫食物,而1只工蜂幼虫在生长发育期平均消耗139.4mg工蜂幼虫食物。     

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.     

北半球500hPa高度场遥相关指数对我国草地螟成虫物候期与幼虫发生面积的影响

北半球500hPa高度场的遥相关指数(遥相关指数)是一个综合了气温,降水以及气压等众多气象因素的气候变化指数,很多生物学现象都与其有关;为了探究遥相关指数是否对我国的草地螟的发生危害有影响,作者分析了我国草地螟Loxostege sticticalisL.成虫物候期及幼虫发生面积的变化趋势及两者与遥相关指数的相关关系,结果表明:我国草地螟成虫始见期年际间有显著提前的趋势,平均每年提前0.40d,与1—5月极地-欧亚型遥相关指数均值(POL1-5)相关性最大;终见期有显著延后的趋势,平均每年延后1.31d,与6—10月东太平洋型遥相关指数均值(EP-NP6-10)相关性最大;全国草地螟幼虫发生面积年际间有显著增长的趋势,平均每年增长57.07khm2,与1—10月东大西洋型遥相关指数均值(EA1-10)相关性最大。     

Host plant utilization by butterfly larvae in the Andaman and Nicobar Islands (Indian Ocean)

The larval food plants of the butterflies of the Andaman and Nicobar islands have not been studied, although the butterfly fauna per se is fairly well known. For the first time we report the food plants of the larvae of 120 species of butterflies from these islands on the basis of laboratory rearing and field studies. This information is essential for the formulation of management programmes for butterfly conservation on these islands which are known to harbour critical swallowtail and (possibly) danaine faunas.     

The role of the antennae and maxillary palps in mediating food preference by larvae of the tobacco hornworm, Manduca sexta

The role of antennae and maxillary palps in mediating food preferences by Manduca sexta (Johan.) (Lepidoptera: Sphingidae) was examined. Fifth‐instar larvae, having different chemosensory organs remaining after microsurgery, were tested in two‐choice feeding assays using three solanaceous host species Lycopersicon esculentum (Mill.), Datura innoxia (Mill.), and Solanum pseudocapsicum (L.), an acceptable non‐host Raphanus sativus (L.) (Cruciferae), and an unacceptable non‐host Pelargonium hortorum (L.H. Bailey) (Geraniaceae). Larvae had a choice between leaf discs of two plant species or between one species and moist filter paper discs (water). The antennae are fully competent in mediating normal (unimpaired) food preferences for S. pseudocapsicum vs. water and P. hortorum vs. water. Thus, the antennae alone can mediate both acceptance and rejection behaviour. The latter is the first report of such a function in M. sexta. The antennae are partly competent (reduced preference) for S. pseudocapsicum vs. P. hortorum. No antennal competence could be demonstrated using the other plant species tested. The antennae alone are either partly needed (R. sativus vs. water) or not necessary to elicit normal food preferences for the plant species tested. The maxillary palps are fully competent in mediating normal food preference for S. pseudocapsicum vs. water, and D. innoxia vs. water. The palps are partly competent for S. pseudocapsicum vs. P. hortorum and incompetent for the other plant species tested. Thus, the maxillary palps alone could only mediate acceptance behaviour in this study. The need of the maxillary palps in normal food preferences could not be demonstrated. Interestingly, the maxillary palps alone can mediate food preferences for two normally rejected plants, R. sativus and P. hortorum. Similar results are reported for two other non‐host plant species, Vigna unguiculata (Walp.) (Leguminosae) and Vinca rosea (L.) (Apocynaceae). Perhaps, the maxillary palps inform M. sexta mostly about feeding stimulatory chemicals common to most plant species.     

Increase in respiratory rate during feeding in larvae of the cinnabar moth Tyria jacobaeae

ABSTRACT. This study tested the effect of diet and phase of the feeding cycle on oxygen consumption by fifth-instar larvae of the cinnabar moth Tyria jacobaeae (L.) (Lepidoptera: Arctiidae). There was no significant variation in respiratory rates among larvae fed different diets, which were floral parts, upper, middle and lower leaves of the host plant tansy ragwort, Senecio jacobaea. The respiratory rates ( x ± 95% Cl μlO₂h^-1) of feeding larvae (279.5 ± 30.9) were higher than those of larvae at rest (179.7 ± 12.2), but were not significantly different from those of larvae in the post-ingestive phase (272.8 ± 35.8).
The respiratory rates of feeding larvae increased linearly with the ingestion rate, such that an additional 21.1 μl O₂ were consumed for every mg dry mass of plant material eaten per hour.     

Carnivory and resource-based niche differentiation in anuran larvae: implications for food web and experimental ecology

1.  Food webs represent the paths of material and energy flow through organisms in an ecosystem. Anuran larvae are important components of pond food webs: they are abundant, consume large quantities of food and serve as prey for many organisms. However, there are very basic uncertainties about the feeding ecology of anuran larvae; for instance, as to which trophic level they belong and whether species differ in resource use. Because anuran larvae have been employed in model systems in experimental ecology for decades, these uncertainties could lead to misinterpretation of published experiments, or inadequate designs of experiments directed at general, conceptual issues in ecology.
2.  Using ¹³C and ¹⁵N stable isotope and gut content analyses of free-ranging and enclosed tadpoles of four ranid species ( Lithobates sylvaticus , L. pipiens , L. clamitans , L. catesbeianus ) in the food webs of six wetlands, we tested the following null hypotheses: (i) that anuran larvae are strict primary consumers; (ii) that they are non-selective feeders and therefore exhibit little feeding niche differentiation; (iii) that they are opportunistic consumers and (iv) that their diet remains unchanged through ontogeny.
3.  All four species consumed and assimilated substantial amounts of animal food; bullfrog larvae, in particular, appear to be predatory. Significant feeding niche differentiation among species occurred with respect to the sources of carbon, consumption of animal matter and nutritional quality of food ingested. We further documented opportunistic feeding habits and ontogenetic shifts in diet.
4.  Collectively, these studies revealed complex trophic relationships that might require a reconsideration of the role of anuran larvae in pond food webs, as well as a reinterpretation of results of previous studies employing anuran larvae in model experimental systems.     

Food preferences of tanypodinae larvae (Diptera: Chironomidae)

Analyses of the gut contents of larvae of three species of Tanypodinae, collected from four sites in north-east England and Scotland, invariably showed small particles (1–10 µm²), predominantly of detritus, to be more abundant than large particles (10–100 µm²), mostly algae and diatoms. No animal remains, such as carapaces, head capsules and chaetae, or vascular plant fragments were found in any of the intestines. In contrast, food-choice and growth experiments suggested that animal food (particularly Tubificidae and Chironominae larvae) was important in the tanypod diet. In the food-choice experiments, six different foods offered to small (4–7 mm long) and to large (8–12 mm long) larvae of Procladius choreus Meigen, were chosen in the following order: live Tubificidae spp.; detritus; live Chironominae larvae; a mixture of algae and diatoms; live Ostracoda spp.; and live Cladocera spp. However, when the results of the individual choices were examined, it was clear that the small larvae had consumed greater amounts of the small types of food (i.e. detritus, algae and diatoms) in comparison to the large larvae. In the growth experiment, those larvae of P. choreus reared solely on Tubificidae, detritus or Chironominae larvae thrived, while those fed on algae and diatoms, ostracods or cladocerans grew more slowly and fewer survived the experimental period.It was concluded that although Tanypodinae larvae are primarily predators with definite food preferences in ideal foraging conditions, in adverse conditions they will utilize a range of available stand-by foods, the most important of which appears to be detritus.     

Toxicity of acephate to larvae of gypsy moth as a function of host plant and bioassay method

We examined toxicity of acephate to third-instar gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), under different conditions of administration method, availability of food to larvae during bioassay, host plant, and activity of detoxifying enzymes. Larvae that had been fed field-collected foliage of white alder (Alnus rhombifolia Nutt.) were less susceptible 48 h after treatment with topically applied acephate if they were allowed to continue feeding on foliage during the bioassay period (LD₅₀= 60.6 μg/g larva ) than if they were not (LD₅₀= 13.5 μg/g larva ). All surviving larvae were replaced on their original food plant after the 48-h bioassay; of these, 14.4% of the larvae not fed during treatment died before pupation, compared with 1.3% of the larvae fed alder during treatment. The LD₅₀ obtained for topically treated larvae reared and treated on Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, (51.1 μg/g larva) was comparable to that obtained for larvae fed alder (60.0 μg/g larva) throughout treatment. Larvae treated orally with acephate, however, were slightly more susceptible when reared on Douglas-fir (LC₅₀, 20.3 ppm ) than when reared on alder (LC₅₀, 27.0 ppm ). Post-treatment mortality in orally treated larvae was 10.3% in those fed alder and 9.5% in those fed Douglas-fir. Higher cytochrome P-450 activities in larvae reared on Douglas-fir apparently did not enhance tolerance to acephate. Both sexes of orally treated larvae took significantly longer to pupate than did controls on both foliage types, as did topically treated males fed Douglas-fir. Pupal weight generally was slightly, but not always significantly, higher in treated than untreated larvae under all dietary and treatment regimes.     

Control of diapause in codling moth larvae

Diapause in a New Zealand strain of codling moth (Cydia pomonella Linnaeus [Lepidoptera: Olethreutidae]) was induced in larvae by photoperiods of 15 h or less. Once diapause had been initiated, it could not be terminated by any combination of conditions tested for at least 20 days after cocooning. In diapausing larvae a low rate of pupation occurred at 25 °C under a long day (18 h) photoperiod. A high rate of pupation was achieved under a long day regime when larvae were decocooned, and provided with apple as nourishment. Diapause could be terminated predictably in 94–100% of larvae by 1) conditioning at 15 °C and constant darkness for periods of 40–100 days, then 2) chilling at 2±2 °C and constant darkness for 20–50 days followed by 3) any post-chill condition periods at 25 °C, 18 h photoperiod. Complete diapause termination was achieved when 100 days conditioning was followed by 30 days or 50 days post-chill period. Under these conditions, 76% termination occurred in the post-chill period after 10 days, and 93% after 25 days.To terminate diapause in codling moth larvae, we recommend that a 100 days conditioning followed by 30 days chilling and 50 days post chilling periods be used.     

Control of spermatogenesis resumption in post-diapausing larvae of the codling moth

The lepidopteran primary spermatocytes produce first eupyrene (nucleated) and later apyrene (anucleated) spermatozoa. The shift to apyrene commitment of the spermatocytes is related to an apyrene-spermatogenesis-inducing factor (ASIF) becoming active towards pupation. During diapause, the primary spermatocytes lyse and spermatogenesis ceases. The renewal of the dichotomous spermatogenesis in the testes of post-diapausing, last-instar larvae of the codling moth was studied in vivo and in vitro. In vivo, the post-diapausing larvae resume the two types of spermatogenesis. Since ASIF activity is related to pupation, the earliest apyrene spermatids appear one day before pupation, as in non-diapausing larvae. In vitro, renewal of spermatogenesis occurs if 20-hydroxy-ecdysone is added to the medium, but only eupyrene spermatids occur since the testes are explanted before ASIF activity has started. These spermatids are unreduced and develop directly from primary spermatocytes which do not undergo meiotic divisions. Moreover, only flagella develop in these spermatids and the nuclei remain spherical. Post-diapause resumption of spermatogenesis is thus a complex process in which meiosis-blocking and meiosis-deblocking factors, ecdysteroids, and the ASIF play regulative roles.     

Algae as first food for cod larvae,Gadus morhuaL.: filter feeding or ingestion by accident?

Cod larvae. Gadus morhua L., 24 days posthatch, were fed different species of algae in order to evaluate both rates and mechanisms of ingestion. The results were compared with cod larvae feeding on a natural assemblage of algae in a lagoon. Small algae (Nannochloris atomus Butcher, 14 pm) were found to enter the larval gut in accordance with drinking rate. In contrast, the cod larvae concentrated larger algae [Dunaliella salina (Dunal) Teodor. 6 10 pm] in the gut at rates from 492 to 7251 times the drinking rate. D. salina was captured in the slits between the visceral arches, and increased activity when the algae was added indicate that the cod larvae are active filter feeders during early larval stages. In the gut of cod larvae from the lagoon the fraction of algal material with diameter larger than 8 pm was 39.2% in 7-day-old larvae while, in 12-day-old larvae it had decreased to 12.6%. The most conspicuous characteristics of gut content in the youngest larvae were green spheres (10 μn) and a naked dinoflagellate (20 μn). Short chains of the diatom Skeletonemu cosrarum (Greville) Cleve were also frequently found.     

How to calculate the optimal density of food for fish larvae

Synopsis The optimal density of plankton required for the growth and development ofCoregonus lavaretus (L.) larvae is calculated on the basis of the volume of water searched, the probability of successful feeding responses, and the results of experimental growth studies. This amounts to 200–260 individual food organisms 1^–1 (individual plankton 0.004 mg), or 14–17 individuals 1^–1 (individual plankton 0.057 mg). The feeding optimum depends on water temperature and the time at which feeding begins.     

四种昆虫饵料对穴蚁蛉幼虫生长发育及消化利用的影响

选择4种可规模化饲养的昆虫——米蛾Corcyra cephalonica、家蝇Musca domestica、斜纹夜蛾Spodoptera litura、甜菜夜蛾Spodoptera exigu幼虫来饲养穴蚁蛉Myrmeleon sagax(Walker)幼虫(俗称蚁狮),研究这4种饵料对蚁狮生长发育及消化利用的影响。结果显示,用家蝇幼虫饲养的蚁狮,其体重增长、相对生长率、化蛹率、蛹重均显著高于用斜纹夜蛾和甜菜夜蛾幼虫饲养的蚁狮,而幼虫历期则比斜纹夜蛾和甜菜夜蛾幼虫饲养的短;用米蛾幼虫饲养,虽然蚁狮体重增长、化蛹率和蛹重与用家蝇幼虫饲养的差异不显著,但其相对生长率却显著低于用家蝇幼虫饲养的蚁狮,幼虫历期也比用家蝇幼虫饲养的明显延长。同时食物消化利用的结果显示,用4种饵料饲养蚁狮,它们的近似消化率差异不显著,但食物利用率和食物转化率均以家蝇幼虫饲养的蚁狮最高。经分析比较,在4种饵料昆虫中,以用家蝇幼虫每4d喂蚁狮1次的饲养效果最佳。     

Effects of microhabitat,time of day,and weather on predation of gypsy moth larvae

Summary Wire cages with different-sized meshes were placed on trunks and around leaves at different heights in oak trees and in forest litter. Gypsy moth, Lymantria dispar, instars II–V tethered with threads were placed in each cage (instars II–III only in leaf cages) as well as outside the cages. Predation of larvae decreased from near ground to mid-crown in trees and was highest in litter and very low on leaves. Predation in litter was not strongly related to cage type, suggesting that small, invertebrate predators were active there, but IV–V instars on trunks were mainly killed by relatively large predators, probably forest mice and shrews. Influences of the time of day and weather on predation were evaluated by observing tethered V–VI instars in litter and on tree trunks hourly. Ants, particularly carpenter ants (Camponotus ferrugineus) and Formica sp., and probably vertebrates, were conspicuous predators in the litter. Ants were most active at lower relative humidities, while other predators were apparently not influenced by humidity. No daily activity rhythms of predation were noted. Invertebrates appear to be important predators of larvae only in the litter whereas vertebrates, such as forest mice and shrews, also readily attack larvae on tree trunks.     

Protein intake by gypsy moth larvae on homogeneous and heterogeneous diets

Abstract. Food selection behaviour, food utilization efficiency and growth performance of a generalist insect, the gypsy moth ( Lymantria dispar (L.), Lepidoptera: Lymantriidae), were examined with respect to variation in food nitrogen concentration. The results suggest that gypsy moth do not suffer physiologically and in fact may benefit from intraplant variation by selective feeding. When provided with diet cubes containing identical nitrogen concentrations, control larvae tended to consume food from a single cube. This behaviour contrasted with that of larvae provided cubes differing in nitrogen concentration. These larvae tended to consume more from the high nitrogen cube, but allocated feeding more evenly among diet cubes than did control larvae. Overall, larvae mixed foods so as to obtain a mean concentration of 2.9-3.2% nitrogen, a concentration assumed to approximate the 'intake target'. Larvae confined to single nitrogen concentrations mitigated the impact of imbalanced diets on body composition via both pre-ingestive and post-ingestive compensation. When confined to a specific nitrogen concentration, larvae adjusted their intake to the point of best compromise. In this case, this was the geometrically closest point to the estimated intake target. Larvae with a choice of foods that deviated more than ±1% from each other in nitrogen concentration grew as well as or better than larvae without a choice but given identical mean nitrogen concentrations. These results demonstrate that selectivity and nitrogen consumption by gypsy moth larvae are altered according to the particular choices available. Insects may benefit from intraplant variation in food quality because such variation provides the opportunity to choose foods and mix them in ways that permit close matching with the intake target. Variation may be particularly important to insects which must offset changing nutritional demands.     

外来害虫蔗扁蛾的寄主范围

综述了我国近年传入的害虫蔗扁蛾的寄主植物范围 :到目前为止 ,蔗扁蛾Opogonasacchari(Bo jer)的寄主植物已达 2 8科 87种 8变种 ;其中国外已报导的为 2 4科 4 6种 4变种 ,中国已查到 1 4科 5 5种 2变种 ,且不断发现新的寄主植物 ,有蔓延到多种行道绿化树木和园林花卉植物上的趋势 ,须引起充分关注。     

Effect of dietary nitrogen on gypsy moth larval nutritional indices, development and lipid content

Nutritional indices, development rates, percent dry weights and total lipids were determined in gypsy moth larvae (Lymantria dispar L.) reared on a high wheat germ (HWG) diet or diets prepared from lyophilized, ball-milled oak or pine foliage as the only source of dietary nitrogen (N). With regard to both total and proteinaceous N content, HWG diet>oak diet>pine diet. All nutritional indices measured were significantly lower in second instars fed pine diet vs. oak diet. Protein supplementation of pine diet with either casein or ovalbumin to bring total N up to the level present in oak diet resulted in small increased in approximate digestibility (AD) and effciency of conversion of ingested food (ECI), but relative growth rate (RGR) remained unaffected. The low RGR of larvae fed pine diet (unsupplemented or protein supplemented), as compared to those fed HWG or oak diet, was accompanied by significantly lower larval percent dry weight and percent total lipid. In contrast, RGR, larval percent dry weight and total lipid values were comparable in second instars fed HWG or oak diet. Insects reared from the first through the final instar on oak diet exhibited lower pupal weights compared to those reared on HWG. Casein addition to oak diet generally resulted in even more extended larval development times and further reduced pupal weights, but wheat germ addition to oak diet did not alter development rates and caused an increase in pupal weights.     

寄主植物对乌桕黄毒蛾取食量及生长发育的影响

【目的】研究乌桕黄毒蛾Euproctis bipunctapex(Hampson)对5种不同科寄主植物(天仙果Ficus erecta var.beecheyana、拐枣Hovenia acerba、苦槠Castanopsis sclerophylla、杨梅Myrica rubra和杜英Elaeocarpus decipiens)叶片的取食量以及不同寄主植物对乌桕黄毒蛾生长发育和繁殖的影响。【方法】在恒定条件[温度(26±1)℃,相对湿度80%,光周期12L︰12D]下,设置5个处理组,每处理分别投喂不同寄主植物叶片,测定取食量、幼虫历期、存活率、繁殖力等指标。【结果】乌桕黄毒蛾对不同寄主植物的取食量差异显著,苦槠饲喂组最高(2 588.15 mg),杜英饲喂组最低(1 971.33 mg);但对不同植物的日取食量总体趋势相同,随时间呈指数增长,4龄起进入暴食期,4龄、5龄和6龄幼虫取食量占总取食量的80.68%~85.91%。取食不同寄主植物的乌桕黄毒蛾生长发育差异显著,天仙果饲喂组的个体幼虫历期(34.35 d)最短,存活率(60.20%)最高,产卵量(281.33粒/雌)最多,而杜英饲喂组的个体幼虫历期(41.36d)最长,存活率(38.78%)最低,产卵量(215.83粒/雌)较少。【结论】乌桕黄毒蛾虫害防治适期是4龄之前,苦槠和杨梅受乌桕黄毒蛾取食最多,天仙果是乌桕黄毒蛾生长发育的最适寄主植物。