Life cycle changes during 12 successive generations of laboratory colonisation of the leafroller Cnephasia jactatana (Walker) (Lepidoptera: Tortricidae) on artificial diet

Abstract

Close monitoring of the lepidopteran leafroller Cnephasia jactatana under laboratory colonisation revealed few distinct effects of successive rearing on artificial diet on the life cycle. The second laboratory generation had a prolonged development time and altered sex synchronism in pupation and eclosion patterns. Some deleterious changes were observed in later generations, including decreases in fertility, egg hatch and sperm motility, failure of mating adults to separate, and pupal and adult malformations. These changes were not adaptive, but were due to incompatibility with the general purpose diet (GPD) used; they were absent under sub-colonisation on a sheepnut-bean based diet (SBD). Success in the laboratory colonisation of C. jactatana is attributed to a random mating protocol, choice of environmental conditions representing the wild habitat, and a rapid rate of population growth.     

Artifical diets and rearing of the nun moth, Lymantria monacha

Artificial diets were reviewed and two tested. The highest level of survival to the adult stage (72%) was obtained on a modified diet of Odell & Rollinson (1966). Rearing required 61 days for males and 70 days for females. Wing deformation occurred in 16% of the adults. The sex ratio ( : ) was 0.80. Average pupal weight was 281 mg for males and 368 mg for females. Females averaged 102 eggs (range 80–125 eggs). Neonates from field-collected egg masses started hatching on 6 December; frost was not necessary for hatching. Hatching could be postponed until at least 10 November of the following year by storing egg masses at-2°C. L. monacha can be maintained continuously in the laboratory.

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Zusammenfassung Eine Massenvermehrung der Nonne, Lymantria monacha (L.), trat in 1984 auf 500 ha Pinus sylvestris bei Budelerbergen (S.O. der Niederlande) auf und betraf 1985 eine Fläche von 2800 ha. Obwohl die Vermehrung durch eine Luftapplikation mit Dimilin 25 bekämpft werden konnte, wurden Untersuchungen begonnen zur Entwicklung von für die Umwelt sicheren Bekämpfungsmethoden, besonders die Anwendung von Virosen. Das Ziel bestand in der Virusproduktion in künstlichen Raupenzuchten. Die Nonne wurde bisher mit verschiedenen für andere Insektenarten oder speziell für diesen Zweck entwickelten künstlichen Nährböden gezüchtet. Da die Zusammensetzung dieser Nährböden und die Zuchtmethoden nicht veröffentlicht waren und da wenige Details über die Raupenentwicklung vorlagen, wurden modifizierten Nährböden von McMorran sowie von Odell & Rollinson für die Massenzucht der Nonne geprüft.

     

In vitro culture of Trichogramma pretiosum on an artificial medium

The composition of an artificial medium and environmental conditions are described for the in vitro rearing of the egg parasite Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae). The medium was composed of defined amounts of protein, carbohydrates, lipid, salts, and vitamins, but also contained up to 40% insect hemolymph. The hemolymph was necessary to induce pupation. T. pretiosum eggs were obtained by dissection of Heliothis virescens (F.) (Lepidoptera: Noctuidae) eggs. In vitro reared T. pretiosum were similar in size to H. virescens reared T. pretiosum, and females were fecund.

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Résumé Les oeufs de Trichogramma pretiosum ont été obtenus par dissection d'oeufs d'Heliothis virescens. T. pretiosum Riley (Hymenoptère, Trichogrammatidae) a été élevé avec succès sur un substrat synthétique. Outre des quantités définies de protéines, glucides, lipides, éléments minéraux et vitamines, la ration contenait aussi jusqu'à 40% d'hémolymphe de Manduca sexta. L'hémolymphe était nécessaire pour induire la nymphose. En plus de la nourriture, les conditions d'environnement sont apparues extrêmement importantes pour élever T. pretiosum dans des conditions satisfaisantes. Le contrôle de l'humidité relative, en particulier, était le facteur le plus important. Les adultes produits au cours de cette étude étaient d'apparence normale; ils se sont accouplés sans problèmes, les femelles étaient fécondes et leur taille ne différait pas de celle d'individus élevés sur H. virescens.

     

Larval development of Diploptera punctata reared alone and in groups

Larvae of the cockroach Diploptera punctata were reared in isolation, in pairs, or in groups of 8–10. Duration of larval development, age at each ecdysis, weights at birth and ecdyses, and adult head-capsule width were measured. Duration of larval development was longer and adult size was larger in isolated animals than in animals reared in pairs and groups. The effect of isolation on development was more pronounced in males. All females had 4 larval instars, whereas males had 3 or 4 instars. The proportion of males with 4 larval instars was higher among animals reared in isolation. There was no difference in the duration of larval development or adult size between pair- and group-reared animals. The sex of animals in the group did not affect adult size or the duration of larval development. Males which underwent 3 or 4 larval instars had different schedules of moulting. Rates of growth of males of both instar types reared in isolation and pairs were similar. Greater adult weight of isolated animals and 4-instar-type males was a result of their longer duration of larval development. Both a higher rate of growth and longer duration of larval development contribute to the larger adult size of females than males.     

The effects of early experience on adult copulatory behavior in zoo-born chimpanzees (Pan troglodytes)

This paper examines the relationship between the early rearing experience of zoo-born, zoo-reared chimpanzees (Pan troglodytes) and the subsequent occurrence of successful copulation as adults. Developmental histories were acquired for 71 subjects via questionnaires and phone interviews. The following variables related to aspects of chimpanzees' early rearing experience were examined: (1) Rearing conditions, that is, hand reared alone, reared with siblings or peers, or reared by at least one adult conspecific. (2) Age removed from mother. (3) Sex of subject, and/or (4) participation in shows. Each of these variables was then compared to the subjects' sexual competence, defined here as having been observed to exhibit functional copulatory behavior as adults. Seventy-five percent of the subjects were observed to exhibit functional copulatory behavior on at least one occasion. No single component of rearing was successful in producing sexually competent adults 100% of the time; no rearing condition, as defined in this study, resulted in reproductive failure for all subjects experiencing those conditions. Chimpanzees that were hand reared alone, that is, in the total absence of conspecifics, were least likely to copulate as adults; about half of those chimpanzees that were reared with siblings or peers (and in the absence of adult conspecifics) copulated as adults. Almost 90% of those chimpanzees that were reared with at least one adult conspecific copulated as adults. Chimpanzees removed from their mothers at an early age (less than one year of age) were less likely to reproduce as adults. Male and female chimpanzees were equally likely to reproduce as adults. Participation in shows or demonstrations appeared to have no effect on chimpanzees' ability to copulate as adults. © 1994 Wiley-Liss, Inc.     

Are brood sex ratios adaptive?—The effect of experimentally altered brood sex ratio on nestling growth,mortality and recruitment

Brood sex ratios (BSRs) have often been found to be nonrandom in respect of parental and environmental quality, and many hypotheses suggest that nonrandom sex ratios can be adaptive. To specifically test the adaptive value of biased BSRs, it is crucial to disentangle the consequences of BSR and maternal effects. In multiparous species, this requires cross-fostering experiments where foster parents rear offspring originating from multiple broods, and where the interactive effect of original and manipulated BSR on fitness components is tested. To our knowledge, our study on collared flycatchers (Ficedula albicollis) is the first that meets these requirements. In this species, where BSRs had previously been shown to be related to parental characteristics, we altered the original BSR of the parents shortly after hatching by cross-fostering nestlings among trios of broods and examined the effects on growth, mortality and recruitment of the nestlings. We found that original and experimental BSR, as well as the interaction of the two, were unrelated to the fitness components considered. Nestling growth was related only to background variables, namely brood size and hatching rank. Nestling mortality was related only to hatching asynchrony. Our results therefore do not support that the observed BSRs are adaptive in our study population. However, we cannot exclude the possibility of direct effects of experimentally altered BSRs on parental fitness, which should be evaluated in the future. In addition, studies similar to ours are required on various species to get a clearer picture of the adaptive value of nonrandom BSRs.     

人工饲养条件下马来熊(Helarctos malayanus)生长发育和行为特点的初步研究

1987年9月至1989年8月,笔者对来自云南瑞丽的2只雄性马来熊成体和7只幼体(3♂,4♀♀)在人工饲养条件下进行了观察研究,本文报道在不同生长时期的不同饲料配方、幼熊感觉器官的发育、齿式的形成、外部形态的变化、体重的生长方法及行为。     

Response of predatory mites with different rearing histories to volatiles of uninfested plants

The behavioural response of the predatory mite Phytoseiulus persimilis to volatiles from several host plants of its prey, spider mites in the genus Tetranychus, was investigated in a Y-tube olfactometer. A positive response to volatiles from tomato leaves and Lima bean leaves was recorded, whereas no response was observed to volatiles from cucumber leaves, or leaves of Solanum luteum and Solanum dulcamara.Different results were obtained for predators that differed in rearing history. Predators that were reared on spider mites (Tetranychus urticae) on Lima bean leaves did respond to volatiles from Lima bean leaves, while predators that had been reared on the same spider mite species but with cucumber as host plant did not respond to Lima bean leaf volatiles. This effect is compared with the effect of rearing history on the response of P. persimilis to volatile allelochemicals of prey-infested plant leaves.     

Three viruses found in the braconid parasitoid Microplitis croceipes and their implications in biological control programs

Productivity and longevity decreased in a laboratory colony of the parasitoid wasp Microplitis croceipes (Cresson) (Hymenoptera: Braconidae). Using light microscopy, it was determined that the colony was free of microsporidia. However, samples of the colony examined for pathogens by electron microscopy revealed three types of viruses: a nonpathogenic polydnavirus which is produced by all female wasps; a nonoccluded baculovirus which is pathogenic to late-stage pupae and adults; and a picorna-like virus which is present in larvae, pupae, and adults. The nonoccluded baculovirus was eliminated from the laboratory colony of M. croceipes by selection of progeny from wasps which had oviposited within 2 to 3 days after emergence from the cocoons and which had lived for at least 14 days post-emergence. Upon death, the wasps were examined by negative stain electron microscopy and only progeny from baculovirus-free wasps were retained. Parasitoid colonies should be systematically examined for pathogenic viruses that may reduce their productivity and efficacy as biological control agents. In addition, exotic parasitoids and predators should be evaluated for viruses and other pathogens while in quarantine.