Xenochironomus canterburyensis (Diptera: Chironomidae), a commensal of Hyridella menziesi (Lamellibranchia) in Lake Taupo; features of pre-adult life history

Abstract

The larvae and pupae of the univoltine chironomid Xenochironomus canterburyensis (Freeman) are inquiline commensals of the freshwater mussel Hyridella menziesi (Gray). The 1st- and 2nd-instar larvae enter the mantle/valve cavity of the mussel in midsummer, and by early winter migrate as 3rd-instar larvae to the posterior end of the valve to lodge near its margin beside the inhalant siphon. During the spring, growth of the periostracum of the valve margin between the larva and the mantle of the mussel leaves the 4th-instar larva outside the mantle/valve cavity, where it pupates before leaving the mussel for the lake surface and adult emergence.     

New diagnosis for genus Austrothaumalea,and redescription of A. neozealandica (Diptera: Thaumaleidae)

Abstract

A new diagnosis of Austrothaumalea Tonnoir is given. The male and female of A. neozealandica are redescribed, and the larva and pupa are described for the first time.     

Immature stages of Curculionidae: the ‘rat-tailed’ larva and the pupa of Notonesius aucklandicus (Phrynixinae)

Abstract

The larva and pupa of Notonesius aucklandicus Kuschel, living in saturated peat soil on the Auckland Islands, some 500 km south of New Zealand, are described and figured. The ‘rat-tail’ type of aquatic adaptation in the larva appears to be unique among Coleoptera, although an evolutionary progression towards it can be traced among Indian weevils.     

Description of the xylobiont larvae and pupae of the genus <Emphasis Type="Italic">Achyrolimonia</Emphasis> (Diptera,Limoniidae)

The larva and pupa of Achyrolimonia basispina (Alex.) are described for the first time. New data on the morphology of the larva and pupa of A. decemmaculata (Loew) are discussed, and the morphological characteristics of the genus are defined more exactly. The larvae of these species develop in the dead wood of deciduous trees and in the old carpophores of wood fungi.     

Prothoracicotropic hormone bioassay: Bombyx larva assay

Summary

An assay for the prothoracicotropic hormone (PTTH) has been established using in situ activation of the prothoracic glands (PG) of Bombyx mori in its larva-to-larva development. The timing of PTTH release was estimated by examining developmental response of 4th instar larvae to brain removal and neck ligation, and changes in the haemolymph ecdysteroid titer and ecdysone-releasing activity of PG in vitro during the development. Injection of Bombyx brain extracts into 4th instar larvae neck-ligated shortly before full activation of PG elicited larval moulting rather than precocious pupation in headless larvae. This developmental shift was regarded as due to the action of PTTH, and the PTTH unit has been defined from a linear log dose-response relationship. Materials chromatographically fractionated from Bombyx brain extracts were examined for the presence of stage- and species-specific PTTH molecules by using this Bombyx larva assay and Bombyx and Samia pupa assays previously developed. The same fractions were active when assayed by Bombyx larva and pupa assays.     

Life history stages and taxonomy of Austrosimulium (Austrosimulium) tillyardianum (Diptera: Simuliidae)

The male, female, pupa, 9th‐instar larva, and egg of Austrosimulium (Austrosimulium) tillyardianum Dumbleton, 1973, are redescribed, and larval instars one to eight are described and morphologically differentiated for the first time. The relationship of A. (A.) tillyardianum to other New Zealand species is briefly reviewed.     

A description of preimaginal stages of Pseudaspidapion botanicum Alonso-Zarazaga & Wang, 2011 (Apionidae,?Curculionoidea)

The preimaginal stages including egg, mature larva and pupa of Pseudaspidapion botanicum Alonso-Zarazaga & Wang, 2011 were described and figured, diagnostic characters of larva and pupa were discussed, and corresponding biological information was supplied. The nomenclature of frontal setae in the larva compared with curculionid weevils, the absence of the hypopharyngeal bracon in the larva, and the metafemoral setae in the pupa were discussed. Common and different characters among the larvae of Pseudaspidapion botanicum, Aspidapion radiolus (Marsham, 1802) and Aspidapion aeneum (Fabricius, 1775) were also provided.     

Crowding inhibits pupation inTribolium freemani: contact chemical and mechanical stimuli are involved

The relationship between the development ofCoccinella septempunctata brucki Mulsant (Coleoptera: Coccinellidae) and its parasitoid,Perilitus coccinellae (Schrank) (Hymenoptera: Braconidae) was studied at two photoperiods (L 16:D8 and L 12: D12) at 26°C. The development ofP. coccinellae is well synchronized with the physiological state of the host,C. septempunctata, which can be parasitized not only as adult but also as larva or pupa. The parasitoid larva completed larval development within 19 days in a non-diapausing host, while in diapausing adults as well as in pupae held at diapause-averting conditions, the parasitoid larva ceased growth at the first instar. Growth was resumed when diapause of the host terminated or by the emergence of the adult host from the pupa. About 550 spheric cells, teratocytes, were liberated into the host hemocoel when the parasitoid egg hatched. The teratocytes increased in size in the active host, while their development was arrested in the diapausing host. Application of methoprene caused diapause termination of both host and parasitoid larva. The results indicate that the development of the larva ofP. coccinellae depends on the physiological conditions of the host,C. septempunctata brucki. The host-parasite relation thus represents an ‘endogenous synchronization’ in the sense of Schoonhoven's definition.     

The immature stages of Hylurdrectonus araucariae Schedl and H.piniarius Schedl (Coleoptera: Scolytidae: Hylesininae)*

The egg, larva and pupa of Hylurdrectonus araucariae and H.piniarius, are described and illustrated in detail. Notes on their biology and ecology are included.     

Parasitoid genus‐specific manipulation of orb‐web host spiders (Araneae,Araneidae)

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Studies on Chironomidae in experimental recirculating stream systems. I. Orthocladius (Euorthodadius) calvus sp.nov.

SUMMARY.

• 1 Large nutnbers of a previously undescribed species of Orthocladius (Euorthocladius) were amongst the first animals to colonize a pair of artificial recirculating streams.
• 2 The larva, pupa and adults are described and compared with O. (E.) thienemanni which occurs abundantly in adjacent streams.

     

The development stages of limnophyes globifer (Lundström) (diptera: chironomidae)

The larva, pupa and adult female of Limnophyes globifer (Lundström) are described for the first time, and the adult male is redescribed from material from a greater geographic range than hitherto. A lectotype is designated for L. globifer and it is suggested that Limnophytes folliculatus Saether is a junior synonym of L. globifer.Entomology Department, British Museum (Natural History)     

Life cycle of <Emphasis Type="Italic">Aylax hypecoi</Emphasis> (<Emphasis Type="Italic">Insecta: Hymenoptera: Cynipidae</Emphasis>), a gall inducer on <Emphasis Type="Italic">Hypecoum</Emphasis> ssp. (<Emphasis Type="Italic">Papaveraceae</Emphasis>)

The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering stage, adult emergence and flying periods, and egg productivity were studied also.     

Morphology of the adult and juvenile stages of Microtendipes rydalensis (Edw.) comb. nov. (Diptera,Chironomidae)

The adult male of Polypedilum rydalensis (Edw.) is described in greater detail than hitherto and the female, pupa and larva are all described for the first time. On the basis of the morphology of the adult and immature stages rydalensis is placed in the genus Microtendipes Kieffer.     

Die motorische aktivität der endoparsitischen Larven vonPimpla turionellae L. undPimpla flavicoxis Ths. [Hym., Ichneum.] in der wirtspuppe

Zusammenfassung Die endoparasitischen Larven der beiden nahe verwandten PuppenparasitenartenPimpla turionellae undPimpla flavicoxis legen w?hrend ihrer Larvenentwicklung in der Wirtspuppe eine charakteristische Wanderung zurück. Unabh?ngig von der Lage des Parasiteneies in der Puppe wandert die Junglarve sofort nach dem Verlassen des Eies zum Kopfende der Puppe und zerst?rt dort das Gehirn und die umliegenden Organe. Anschliessend kriecht sie ins Abdomen, w?hrend sie gleichzeitig die Wirtsgewebe aufl?st und Nahrungsbrei zu sich nimmt. Im Abdomen dreht sie sich abermals um, so dass ihr Kopf zum Vorderende der Puppe weist. In dieser Lage verzehrt sie den Rest des verflüssigten Puppeninhalts und verpuppt sich. Die Parasitenimagines schlüpfen durch das Vorderende der Wirtspuppe. —In superparasitierten Puppen wandern alle Junglarven zum Kopfende der Wirtspuppe und tragen dort ihre Konkurrenzk?mpfe aus, indem die überz?hligen Larven durch Bissverletzungen ausgeschaltet werden. In der Regel bleibt eine Larve am Leben und entwickelt sich weiter. — Die Junglarven werden wahrscheinlich durch chemische oder Str?mungsreize zum Vorderende der Puppe gelenkt. Dieses ausgepr?gte Orientierungsverhalten gestattet die Ausschaltung gleichalteriger Nahrungskonkurrenten zum frühest m?glichen Zeitpunkt. Die Wanderung der Larven bringt den Parasiten allem Anschein nach noch andere Vorteile.

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Summary The endoparasitic larvae of two pupal parasites,Pimpla turionellae L. andPimpla flavicowis Ths. (Hym., Ichneumonidae) move inside the host pupa (Galleria mellonella L.) in a characteristic manner during their development. Soon after hatching from the eggs the young larvae arrive in the head of the pupa (tab. 1 and 6) and destroy the organs situated here by histolysis. As is shown in tables 2, 3, 4 and in figure 2 the movement of the larvae to the head region is independent of the site of the egg in the pupa. One or two days afterwards the larvae change their position by moving into the abdomen, liquefying its contents (fig. 3). They turn again in the abdomen but remain there feeding on the rest of the liquified host tissues. The fullgrown larva lies in the abdomen occupying nearly the whole cavity of the pupa. Its head is directed towards the head part of the pupa. Pupation is usually performed in this position so that the adult emerges from the anterior end of the host pupa. When the host pupa is superparasitized byP. turionellae, all young larvae move to its anterior end. The competing larvae fight each other, using their mandibles for wounding the soft body of their competitors. These wounds seem always to be fatal and can be recognized by their rapid melanization (fig. 4). Since all young larvae have met in the head region of the pupa, the dead competitors can usually be found there in full number, the victor having moved into the abdomen next day (tab. 5). Only a single larva survives. The young larvae seem to be directed by a chemical attractant or by rheotaxis in the circulating hemolymph, since gravity and light can be excluded as factors of orientation. The behaviour of the larvae enables the parasites to eliminate competitors of the same age at the earliest possible moment and in this way to conserve all the food for the surviving larva. Further advantages are probably gained by the circulating movement of the larvae, i.e. the early elimination of the hormonal control system of the host and the final position of the fullgrown larva, which leads the emerging adult to openings in the cocoon or gallery preformed by the host larva.

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Pimpla flavicoxis Гhs=Pimpla aquiloniaCress (Aubert, 1969).     

Pupal polymorphism in the butterfly Danaus chrysippus (L.): environmental, seasonal and genetic influences

The pupae of the tropical butterfly Danaus chrysippus are either green or pink the switch being operated by a ‘greening’ hormone produced in the larval head. Both environmental and genetic cues are involved in controlling the endocrine mechanism. The environmental factors identified are of two distinct kinds: proximate factors influence pupal colour after the larva has selected its pupation site, whereas ultimate factors are effective at an earlier stage, either prompting choice of pupation site by the larva or priming pupation physiology in a particular direction. Genetic factors preadapt the larva to form a pupa which will be cryptic in the normal or average conditions, climatic or biogeographical, anticipated in its environment. The proximate factors demonstrated are background colour, darkness, light quality (wavelength) and humidity. There is some evidence that substrate texture may also be relevant. Ultimate factors are temperature, humidity and species of larval foodplant. Two closely linked gene loci which govern the phenotype of adult morphs and races either have a pleiotropic effect on pupa colour or are closely linked with other genes which do so. Moreover, the two loci interact epistatically with respect to their pupation effects. Factors producing predominantly green pupae are plant substrates, yellow background, darkness, yellow light, high humidity, high temperature, the b allele at the B locus when homozygous and, on non-plant substrates, the C allele at the C locus. High frequencies of pink pupae result on non-plant substrates, red backgrounds, in blue light, low humidity, low temperatures and in B- and cc genotypes. The C locus alleles, C and c, interact epistatically with the B alleles, their effect on choice of pupation site being determined by linkage phase. Of the two foodplants tested, Calotropis produced a high frequency of green pupae and Tylophora of pinks. The seasonal cycling of rainfall, temperature, availability or condition of foodplant, and gene frequencies are all correlated with oscillations in the frequencies of green and pink pupae. Though genotype influences pupa colour, all genotypes are capable of forming pupae of both colours. The variation can therefore be attributed to an environmental polyphenism superimposed upon a genetic polymorphism. The hormone producing green pupae emanates from the head during the prepupal period. Denied hormonal influence, the pupa is pink. Pupal colour is judged to be aposematic at close range and cryptic at distance.     

Early Stages and Biology of Melitaea robertsi Butler, 1880 (Lepidoptera,Nymphalidae)

The external morphology of the egg (including the chorion), the last instar larva, and the pupa of Melitaea robertsi Butler, 1880 from East Iran is described; data on the host plant of the species are given.

     

The Pupa and Larva of Propsilocerus taihuensis (Wen,Zhou & Rong) (Diptera: Chironomidae), with Complete Keys to all Immatures of the Genus Propsilocerus

The pupa and larva of Propsilocerus taihuensis (Wen, Zhou & Rong, 1994) are described for the first time. Both are close to P. akamusi (Tokunaga). The phylogenetic argumentation of the genus outlined in Sæther and Wang (1996) is confirmed. Revised keys to larvae and pupae of the genus are given. The main morphological characters of the different species of the genus are compared in tables.