The ontogeny of appendages and carapace of Neonesidea schulzi (Ostracoda: Bairdiidae) from the Red Sea coast,Egypt

The ostracod genus Neonesidea is broadly distributed in shallow marine waters. The ontogeny of the N. schulzi (Bairdiidae) is described in detail by studying the development of the appendages and variations in carapace form, size and structure. Neonesidea schulzi has eight post-embryonic instars, and a gap in its ontogenetic development during instar A-6, where no new Anlage is added. The Anlagen of the copulatory organs and the forked terminal claw of second antenna appear in the seventh (A-1) instar, and the first thoracic legs of podocopid ostracods are shown to descend from the thoracic region. For the first time in ostracods, observations of moulting from sixth and seventh instars are presented.     

The growth, development and reproduction of a deep sea cumacean (Crustacea: Peracarida)

A single sample of over 1000 individuals of Leuconjonesi Bishop, 1982, taken at a depth of about 1500 m on the continental slope off Surinam, was studied. The carapace length of individuals in the first postmarsupial instar was already about half that of brooding females. Growth increments at early moults were of 20–25. Males reached the final morphological form in the sixth postmarsupial instar. A prepuberty moult was recognized between the third and fourth male instars. Females reached the preparatory stage in the fourth postmarsupial instar. Brooding condition occurred for the first time after the next moult. The brooding form could then alternate at successive moults with an inter-brood form, resembling the preparatory female, with small, non-overlapping oostegites. Preparatory and inter-brood females were morphologically separable; vitellogenesis was restricted to these instars. Broods were of 6–12 young. The individuals in each brood probably completed marsupial development, and were released, one by one. The copepod parasite Sphaeronella infested 10", of brooding-form females.     

The life stages and population dynamics of an arid zone scorpion Urodacus yaschenkoi (Birula 1903)

The arid zone scorpion Urodacus yaschenkoi (Birula 1903) is shown to have six instars. Instars can be recognized by measuring the claws and the carapace plus first five tail segments. A population study, carried out at Coombah, NSW, showed that the life history consisted of mating in September–October, 18 month gestation, birth in February-March, moult to second instar March-April and annual moults to sixth instar in December–February. The minimum generation time was 6 y, and the population appeared to be stable. The calendar of catches method was used to determine the population size (about 400 animals in 2240 m²) but required some extra assumptions to cope with loss of marks from individuals when they moulted.     

The Ontogeny of Neonesidea oligodentata (Bairdioidea, Ostracoda, Crustacea)

This is the first detailed ontogenetic study of the appendages and carapace of a bairdioidean ostracod. This paper uses the development of the appendages and changes in the pore systems of the carapace through ontogeny to help determine the relationship between the Bairdioidea and other podocope groups. Neonesidea oligodentata has eight post-embryonic stages: one fewer than the Cypridoidea, Cytheroidea and Darwinuloidea. The first instar of N. oligodentata resembles that of the second instar of the Cypridoidea and Cytheroidea in terms of appendages, and it is postulated that there is an additional instar stage of N. oligodentata that molts within the egg. The general sequence of appearance of the limbs from instar A-7 onwards is similar to that of the Cypridoidea and Cytheroidea, but different from that of the Darwinuloidea. Like the Cypridoidea and Cytheroidea, N. oligodentata has a gap in its ontogenetic development during instar A-6, where no new Anlage is added. Pore system analysis of A-7 instars suggests that the Bairdioidea may be more closely related to the Cypridoidea than to the Cytheroidea.     

The ontogeny of Loxoconcha japonica Ishizaki, 1968 (Cytheroidea, Ostracoda, Crustacea)

The ontogeny of the cytheroidean species Loxoconcha japonica is documented from the earliest instar to the adult. The first instar (instar A-8) of L. japonica is different from that of cypridoidean species in that it has an additional appendage, the furca, present. From instar A-7 onwards, the appearance of the appendages is similar to that of cypridoidean and bairdioidean species. The furca is well developed in instars A-8 to A-5, and is probably an important appendage in these early instars, despite its reduced form in the adults. Some appendages of L. japonica (e.g. the antennae) gain very few setae and claws through ontogeny, compared with species from other superfamilies. This possibly reflects paedomorphic evolution of this species.     

Taxonomy and sexual dimorphism of a new species of Loxoconcha (Podocopida: Ostracoda) from the Pleistocene of the Japan Sea

A new ostracod, Loxoconcha kamiyai sp. nov. in the Family Loxoconchidae, is described from the Pleistocene Omma Formation of Japan. Its geological and geographical distributions suggest that this species was once endemic to the Japan Sea, where it would have evolved until the Pliocene. Since the early Pleistocene, this species would have become extinct within this marginal sea during glacial maxima, probably due to its narrower salinity tolerances and geographical distributions than those of extant species inhabiting the euryhaline environments in other seas. The distributional patterns of pore systems in this species strongly suggest its closest phylogenetic affinities to a living species, Loxocorniculum mutsuense . These two species show a unique adult sexual dimorphism in the anterior element of the hingement. Taking the female hingement morphology as a standard, the male hingement can be explained in terms of heterochrony, i.e. paedomorphosis. Sexual hingement dimorphism with paedomorphosis occurs in only one phylogenetic group of the genus Loxoconcha , which is distinguished by the ontogenetic distributional patterns of pore systems. This morphology may represent relict primitive characters of ancient ostracods and could be an important character for evaluating the history of sexual dimorphism in ostracods since the Palaeozoic.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 153 , 239–251.     

Studies on feeding and trophallaxis in the subterranean termite Odontotermes formosanus using rubidium chloride

Differences in feeding and trophallaxis among castes of the fungus‐cultivating higher subterranean termite Odontotermes formosanus Shiraki (Isoptera: Termitidae) were determined using rubidium (Rb) as a tracer. In the feeding study, workers and third instars fed directly on Rb‐treated filter paper and acquired the highest levels of Rb content. Although fifth and sixth instars obtained the Rb content over the marked level, the feeding ability of the caste was very poor. However, soldiers did not feed on Rb‐treated filter paper. In the trophallaxis study, worker, soldier, and fifth‐ and sixth‐instar recipients paired with Rb‐fed worker donors had a significantly higher Rb content than those paired with control donors. Results indicate that soldiers are completely dependent on workers for nutrition. Workers and fifth and sixth instars may obtain nutritional material from foraging workers. When third‐instar recipients were paired with Rb‐fed worker donors, they did not have a significantly higher Rb content than when they were paired with control donors, suggesting that the frequency of worker/third instar trophallaxis was very low. Transfer efficiency from the four trophallactic combinations ranged from 1.2 (worker donors to third‐instar recipients) to 12.9% (worker donors to soldier recipients). Accordingly, nutritional material from foraging workers could be transferred to non‐foraging workers, soldiers, and fifth and sixth instars by trophallaxis; however, third instars rarely obtain nutritional material from foraging workers, because they are capable of feeding within the nest.     

警纹夜蛾幼期虫龄区别的研究

通过观察脱皮法、测量头壳宽度法等,描述了警纹夜蛾幼期各虫龄的形态特征并加以比较,同时发现六龄幼虫具有二型现象。     

Copulatory behaviour and sexual morphology of three <Emphasis Type="Italic">Fabaeformiscandona</Emphasis> Krstić, 1972 (Candoninae,Ostracoda, Crustacea) species from Japan,including descriptions of two new species

Two new species of Fabaeformiscandona and collections of Fabaeformiscandona japonica (Okubo, 1990. Bulletin Biogeography Society of Japan 45: 39–50) from Japan have provided an opportunity to study the copulatory behaviour and sexual morphology of these species. The male uses the large fifth limb palps to force open the female carapace for copulation. However, the female has an enlarged overlapping flap over the posterior of the carapace which appears to hinder the male from opening the carapace, thus the female retains some control over potential mates. During copulation, the males’ fifth limbs, caudal ramus and m process of the hemipenes and the females’ protrusion of the female reproductive organ play a crucial role in providing a secure interface between the sexual organs to allow for the transfer of the giant spermatozoa. Development of the sexual organs in both sexes begins during the A-2 instar, and the protrusion of the female genital lobe begins to form during the A-1 instar.     

Ontogenetically stable dimorphism in a lacertid lizard (Acanthodactylus boskianus) with tests of methodology and comments on life-history

Recent arguments in the literature prompted us to compare methods for assessing sexual dimorphism in body proportions of lacertid lizards, using Acanthodactylus boskianus . Although expressing body-part measurements as proportional to head length was the most effective method, we recommend using trunk length for the baseline as a general method for lizards. We also argue that, when aiming to assess sexual dimorphism in body proportions of lizards, if the context is ecological, all available adults should be included. However, for morphology and taxonomy, small sub-samples of the largest individuals that maximally express their genetic morphological potential should be used. In A. boskianus , the sexual dimorphism of mensural characters in adults was typical: males were larger, with relatively larger head and appendages. However, the ontogeny of this dimorphism was unusual in that the differences existed already in youth and thereafter persisted isometrically. The sexual dimorphism of meristic characters was male-biased in numbers of femoral pores and of caudal vertebrae, and female-biased in numbers of ventral plates along the trunk and of precaudal vertebrae. Size dimorphism may conceivably play a role in sex recognition because two potential visual cues (i.e. size dimorphism and dichromatism) appear to complement each other.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society 2009, 97 , 275–288.     

The life history and culturing of Xestoleberis hanaii (Crustacea,Ostracoda)

Xestoleberis hanaii Ishizaki, 1968 is one of the most abundant species on the Japanese coast and can be collected in all seasons from intertidal calcareous algae on rocky shores. Several characteristics make this species a suitable `experimental animal' in the laboratory: (1) adaptability to artificial environments (room temperature, petri dish, artificial seawater, single cultured food-type), (2) high fertility (active copulatory behaviour, egg brooding within the carapace, high egg productivity) and (3) rapid growth rate. Females mate after the final moult (when the reach sexual maturity); oviposition of fertilized eggs takes place over a period of four days after the final moult. Eggs (about 40 in total) are laid a few at a time in the postero-dorsal brood space of the carapace; they hatch in about 9 d as A-7 instars which are then discharged from the brood space within a day or two. Seven moults take place within the next approx. 33 (female) or 39 (male) days to reach adulthood. Adult females live for about 18 weeks and may repeat the reproductive cycle three times; adult males live for about 14 weeks.     

马尾松毛虫过氧化氢酶及过氧化物酶与耐药性的关系

马尾松毛虫Dendrolimus punctatus幼虫体内存在着过氧化氢酶(CAT)和过氧化物酶(POD)。4龄幼虫的CAT和POD活力较大,其次是6龄幼虫,5龄幼虫的CAT和POD活力较4龄和6龄幼虫低。醚菊酯(etofenprox)处理后,在兴奋期(30 min),CAT和POD活力水平上升。4龄和6龄幼虫在抑制期(50 min以后),CAT和POD活力呈波动式上升,接近死亡时下降。5龄幼虫的CAT和POD活力呈波动式上升,接近死亡时下降。5龄幼虫的CAT在抑制期保持比正常虫体高的活力。结果表明,马尾松毛虫4龄、5龄和6龄幼虫与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫对醚菊酯的耐药力,5龄是4龄的1.43倍,6龄是4龄的1.72倍。因此,药物防治的合理时期应掌握在4龄以前较适宜。     

Life‐history traits in a parasitoid dipteran species with free‐living and obligate parasitic immature stages

The robber fly Mallophora ruficauda Weidemann (Diptera: Asilidae) is an important pest of apiculture in the Pampas of Argentina. As adults, they prey on honey bees and other insects, whereas the larvae are ectoparasitoids of Scarabaeidae grubs. Females of M. ruficauda lay eggs in grassland where the larvae drop to the ground after being wind‐dispersed and burrow underground searching for their hosts. A temporal asynchrony exists between the appearance of the parasitoid larvae and the host, with the parasitoid appearing earlier than the host. The present study investigates whether a strategy of synchronization with the host exists in M. ruficauda and determines which of the larval instars are responsible for it. Survival patterns and duration of the immature stages of the parasitoid are investigated to determine whether there is a modulation in the development at any time that could reduce the asynchrony. Experiments are carried out to determine the survival and duration of free‐living larval stadia in the absence of cues associated with the host. It is established that the first instar is capable of moulting to the second instar without feeding and in the absence of any cues related to the host, a unique event for parasitoids. Also, the first instar of M. ruficauda moults to the second stage within a narrow temporal window, and the second instar never moults in the absence of the host. After parasitizing a host, the second instar has the longest lifespan and is the most variable with respect to survival compared with the rest of the instars. All larval instars, except for those in the last (fifth) stadium, have a similar rate of mortality to that of second‐instar larvae. Additionally, it is established that the host is killed during the fourth (parasitoid) stadium and that the first‐ and fifth‐larval instars develop independently of the host. Finally, possible mechanisms that could aid in compensating for the asynchrony between the parasitoid and the host, promoting the host–parasitoid encounter, are discussed.     

蓖麻蚕个体发育中蜕皮甾类滴度的变化

用放射免疫分析法(RIA)测定了蓖麻蚕(Philosamia cynthia rieini)从卵期到成虫个体发育整个过程的蜕皮甾类(MH)水平.卵期在6天时有一个MH峰.一龄到四龄各龄均有一个MH峰,出现在停食前一天,导致幼虫蜕皮.五龄期有两个MF峰.第一个小峰出现在第三天,使进食的幼虫向预蛹转化;第二个高峰在上簇两天后,导致蛹表皮的形成.与其它鳞翅目昆虫一样,蛹期只有一个MH峰,发生在蛹期的前半段.成虫期血淋巴内MH含量很低.     

Achieving high sexual size dimorphism in insects: females add instars

Abstract.  1. In arthropods, the evolution of sexual size dimorphism (SSD) may be constrained by a physiological limit on growth within each particular larval instar. A high SSD could, however, be attained if the larvae of the larger sex pass through a higher number of larval instars.
2. Based on a survey of published case studies, the present review shows that sex-related difference in the number of instars is a widespread phenomenon among insects. In the great majority of species with a sexually dimorphic instar number, females develop through a higher number of instars than males.
3. Female-biased sexual dimorphism in final sizes in species with sexually dimorphic instar number was found to considerably exceed a previously estimated median value of SSD for insects in general. This suggests a causal connection between high female-biased SSD, and additional instars in females. Adding an extra instar to larval development allows an insect to increase its adult size at the expense of prolonged larval development.
4. As in the case of additional instars, SSD is fully formed late in ontogeny, larval growth schedules and imaginal sizes can be optimised independently. No conflict between selective pressures operating in juvenile and adult stages is therefore expected.
5. In most species considered, the number of instars also varied within the sexes. Phenotypic plasticity in instar number may thus be a precondition for a sexual difference in instar number to evolve.     

马尾松毛虫蛋白质、核酸酶和羧酸酯酶与耐药性的关系

马尾松毛虫(Dendrolimus punctatus Walker)幼虫蛋白质含量、羧酸酯酶和多酚氧化酶活力与虫龄大小成正相关;氰戊菊酯处理后,兴奋期的蛋白质含量和羧酸酯酶活力上升,到抑制期均降低到正常虫体的水平,而多酚氧化酶的变动不大。正常虫体中脱氧核糖核酸酶(DNase)和核糖核酸酶(RNase)的活力存在差异:DNase从3—5龄幼虫随虫体增大而上升,到6龄时明显降低;RNase与虫龄大小成负相关;氰戊菊酯处理后,DNase便开始下降并低于正常虫体的水平,而RNase在兴奋期上升,到抑制期下降亦低于正常虫体水平。结果说明,除多酚氧化酶外,蛋白质、核酸酶和羧酸酯酶均与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫随虫龄增大而耐药力增加,氰戊菊醋对5龄幼虫是3龄的2.8倍,6龄是4龄的2.3倍。因此,掌握在4龄前进行药物防治是合理的。     

Effects of carbon-dioxide anaesthesia on the number of instars,larval duration and adult body size of the German cockroach, Blattella germanica

Effects of repeated carbon-dioxide anaesthesia during larval development on the number of moults, larval duration, and the body size of resulting adults were investigated. Concentration of carbon dioxide administered was 70%, and each period of anaesthesia lasted for 3 min. Anaesthesia administered twice a week until the 3rd instar increased the number of instars required to reach maturity. However, repeated anaesthesia after the 4th instar scarcely influenced the number of instars. On the other hand, repeated anesthesia prolonged larval duration whenever administered during the early or late instars. It is thus suggested that anaesthesia by carbon dioxide during larval development has two distinct effects: increasing the number of moults and prolonging larval duration. The former is stage specific and effective only during early instars, whereas the latter is effective during any particular instars until the last instar. The body size of resulting adults remained almost the same as for controls even after the repeated carbon-dioxide anaesthesia as many as 14 times. Some further observations concerning correlations between the number of moults, larval duration and adult body size are shown, and differences between the sexes regarding the number of instars and larval duration are also presented.     

Size dimorphism in Rankinia [Tympanocryptis] diemensis (Family Agamidae): sex-specific patterns and geographic variation

Sexual dimorphism has implications for a range of biological and ecological factors, and intersexual morphological differences within a species provide an ideal opportunity for investigating evolutionary influences on phenotypic variation. We investigated sexual size dimorphism (SSD) in an agamid species, Rankinia [Tympanocryptis] diemensis , to determine whether overall size and/or relative morphological trait size differences exist and whether geographic variation in size dimorphism occurs in this species. Relative morphological trait proportions included a range of head, limb, and inter-limb measurements. We found significant overall intersexual adult size differences; females were the larger sex across all sites but the degree of dimorphism between the sexes did not differ between sites. This female-biased size difference is atypical for agamid lizards, which are usually characterized by large male body size. In this species, large female-biased SSD appears to have evolved as a result of fecundity advantages. The size of relative morphological trait also differed significantly between the sexes, but in the opposite direction: relative head, tail, and limb sizes were significantly larger in males than females. This corresponds to patterns in trait size usually found in this taxonomic group, where male head and limb size is important in contest success such as male–male rivalry. There were site-specific morphological differences in hatchlings, including overall body size, tail, inter-limb, thigh, and hindlimb lengths; however, there were no sex-specific differences indicating the body size differences present in the adult form occur during ontogeny.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 699–709.