The genus Plectrocnemia Stephens of Japan (Trichoptera; Polycentropodidae)

The Japanese species of the genus Plectrocnemia Stephens (Trichoptera; Polycentropodidae) are revised based on examination of male material. Five new species are described: P. divisa, P. suzukii, P. corna, P. scoparia, and P. odamiyamensis. P. levanidovae Vshivkova et al. is recorded from Japan for the first time and redescribed. P. wui (Ulmer), P. tochimotoi Schmid, P. tsukuiensis (Kobayashi), and P. okiensis Kobayashi are redescribed. Arctopsyche hirayamai Matsumura is transferred to Plectrocnemia and redescribed. P. asuana Kobayashi, P. kadowakii Kobayashi, and P. makiensis Kobayashi are transferred to the genus Nyctiophylax Brauer.     

New species of Plectrocnemia and Nyctiophylax (Trichoptera, Polycentropodidae) from China

Four new species of genus Plectrocnemia and 4 new species of genus Nyctiophylax are described, namely: Plectrocnemia verticalissp. n.; Plectrocnemia acuminatasp. n.; Plectrocnemia cryptoparameresp. n.; Plectrocnemia qianshanensissp. n.; Nyctiophylax (Nyctiophylax) senticosussp. n.; Nyctiophylax (Paranyctiophylax) gracilissp. n.; Nyctiophylax (Paranyctiophylax) pungenssp. n.; and Nyctiophylax (Paranyctiophylax) auriculatussp. n.     

Ultrastructure du labium de la larve du Speophyes lucidulus delarouzeei (Coleoptera,Catopidae)

We successively examined the two main parts of the labium: the ligula and the palps. The organs located on the ligula have a simple innervation and may represent various types of mechanoreceptors. The palps are crowned by 13 different sensilla which have various receptions (mechanoreception, olfaction, gustation). Several described sensilla hold an unknown function.     

A revised key to larvae of the genus Plectrocnemia (Polycentropodidae: Trichoptera) in Britain, with notes on Plectrocnemia brevis McLachlan

SUMMARY. The key distinguishes the previously unknown larva of Plectrocnemia brevis McLachlan from larvae of the other two British Plectrocnemia species, P. conspersa (Curtis) and P. geniculata McLachlan. Notes are given on the larval habitat, life cycle and identification of the adult of P. brevis.     

Location of copper in larvae of Plectrocnemia conspersa (Curtis) (Trichoptera) exposed to elevated metal concentrations in a mine drainage stream

Using histological techniques together with transmission electron microscopy and X-ray microanalysis, copper-containing granules (which also contain significant amounts of sulphur) have been observed in the cells of the malpighian tubules and in the subcuticular region of larvae of Plectrocnemia conspersa. It is suggested that the granules in both these regions are primarily pigment granules, which provide a mechanism for taking potentially toxic concentrations of copper (and possibly other metals) out of circulation. This mechanism of metal tolerance may in part account for the reported occurrence of larvae of P. conspersa in waters with elevated concentrations of trace metals.     

Twenty-four new species of Polycentropus (Trichoptera, Polycentropodidae) from Brazil

Twenty-four new species of the caddisfly genus Polycentropus (Insecta: Trichoptera: Polycentropodidae) occurring in Brazil are diagnosed, described, and the male genitalia of each are illustrated. Eighteen of the new species are placed in the Polycentropus jorgenseni species complex of the Polycentropus gertschi group of New World Polycentropussensu lato. Furthermore, 6 new species within the Polycentropus gertschi group (Polycentropus ancistrussp. n., Polycentropus boraceiasp. n., Polycentropus cariocasp. n., Polycentropus froehlichisp. n., Polycentropus galharadasp. n., and Polycentropus graciosasp. n.) are placed in an informal diagnostic cluster of species with Polycentropus urubici Holzenthal and Almeida. Ten of the other Polycentropus gertschi group species form a second cluster of diagnostically similar species, the Polycentropus soniae cluster (Polycentropus caaetesp. n., Polycentropus carolaesp. n., Polycentropus cheliceratussp. n., Polycentropus fluminensissp. n., Polycentropus itatiaiasp. n., Polycentropus minerosp. n., Polycentropus santateresaesp. n., Polycentropus soniaesp. n., Polycentropus tripuisp. n., and Polycentropus virginiaesp. n.). Two of the remaining 8 new species are included in the Polycentropus jorgenseni species complex (Polycentropus cipoensissp. n. and Polycentropus verruculussp. n.), while the remaining 6 are unique and cannot be placed in one of the groups at this time (Polycentropus acinaciformissp. n., Polycentropus amphirhamphussp. n., Polycentropus cachoeirasp. n., Polycentropus inusitatussp. n., Polycentropus paprockiisp. n. and Polycentropus rosalysaesp. n.).     

Effects of information asymmetries in contests between net spinning caddis larvae (Plectrocnemia conspersa)

Summary During five days prior to the introduction of potential intruder larvae, residents were treated in four different ways. In one treatment the residents were unfed and their nets were taken away at daily intervals. Nets were not taken away in the other treatments, and residents were unfed, fed 2 or 4 items per day, respectively. Small intruders were equally successful as large ones in taking over low energy demanding nets of unfed, disturbed residents whose nets were taken away daily. Take overs of high ranked nets of larvae fed four prey items per day were mainly performed by large intruders. Low investment nets of unfed, disturbed resident larvae were often taken over during the first day upon the implantation of intruder larvae. On the contrary, unfed undisturbed larvae defending a five times as energy demanding net only suffered a slight net loss. Nets of unfed, undisturbed larvae were taken over somewhat more often than those from residents fed two prey per day. The results indicate prior treatment to inform these three resident categories of their resource values. Owners of high ranked nets fed two prey per day were most keen on defence during the first day upon introduction of potential intruders. Residents fed four prey per day suffered from a significantly higher number of take overs during the first day compared with larvae only fed two prey per day. The residents fed four prey per day stored some of the food in their nets making this resource more valuable also to intruders. After five days the number of take overs was about the same irrespective of previous treatment.     

Ultrastructure et maturation de la glande accessoire de la spermatheque chez Speonomus delarouzeei fairm. (Coleoptera : Catopidae) du milieu souterrain

The maturation, histology and ultrastructure of the spermathecal accessory gland of Speonomus delarouzeei (Celeoptera : Catopidae) were studied. The functional units of the epithelium surrounding the gland cavity consist of 2 cells: one secretory cell and one ductile cell, which allows the secretory products to pass into the central lumen. The complete development of this gland takes 24 – 32 days after emergence. When the glandular cells are fully developed, their secretory products reach the pouch of the spermatheca. From then on a high percentage of females copulate.     

Etude de quelques facteurs conditionnant la prise de nourriture chez les larves du criquet migrateur, Locusta migratoria migratorioides (Orthoptera, Acrididae)

Résumé La prise de nourriture a été évaluée en fonction de l'état physiologique de l'insecte: l'appétence alimentaire semble en partie commandée par l'état de réplétion du jabot; cependant, la déficience en métabolites intervient aussi, sans doute en abaissant les seuils sensoriels responsables de l'ingestion.

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Summary Hunger in the nymphs of Locusta migratoria was quantitatized in terms of the duration of feeding and related to the degree of repletion of (1) the entire alimentary canal, and (2) the crop. Appetency appeared to be more closely related to state of repletion of the latter.Moreover, though a deficiency in body metabolites does not seem to augment food intake of highly gustatory materials, this is not the case with less stimulatory substances. Prolonged starvation probably causes a reduction in the response threshold of the sense organs that are concerned with the uptake of food.

     

Influences de la castration et du propionate de testosterone sur le comportement des rats conditionnes par paires

Four groups of 10 male rats (Group A: normal rats, Group B: castrated rats, Group C: castrated rats + 1 mg P.T./day, Group D: castrated rats + 1 dose of 50 mg/kg of P.T. cyclohexane) were avoidance conditioned during nine sessions of 50 trials. They were conditioned individually during sessions 4, 5 and 6 and by pairs during sessions 1, 2, 3, 7, 8 and 9. During these last sessions, all groups presented a low level of acquisition and aggressive behaviour. These phenomena were worsened in the castrated rats whose performances stayed low even when they were conditioned individually. On the other hand, the frequency of their aggressive behaviour was often higher than that of the other groups. The injection of P.T. cyclo-hexane improves the performance of the castrated animals but does not entirely compensate for the differences between control and experimental rats.     

De l'optimisation du nombre de variables morphologiques dans la discrimination entre populations (le cas de l'aile chez Drosophila melanogaster)

Whilst wing size measurements are often used in Drosophila to discriminate between groups of individuals, the choice of the particular characters measured is generally not justified.Statistical and genetical properties of 8 characters measured on the left wing, in three stocks of Drosophila melanogaster were analysed. A multivariate analysis is done by studying correlations between characters and by interpreting the first factor of a principal component analysis.The results shows that only one measurement is sufficient in order to discriminate between the stocks, as far as mean values are concerned; wing length is, in that case, the best character since its variance has a relatively high genetic component. When dealing with correlation among characters as a way of estimating shape, four measurements are needed and sufficient. This shows the necessity of choosing the characters to be measured.     

Influence du groupement social sur la reproduction de la femelle de Microcebus murinus (Miller, 1777)

Microcebus murinus is a photoperiod-dependent polyoestrous seasonal prosimian. In captivity, ♀♀ kept isolated or paired with a ♂ undergo 3 oestruses (April, June, August) during the breeding season. When 2, 3 or 4 pairs are kept together, a 25 % decrease in occurrence of the 2nd and 3rd seasonal oestrus is noticed. Life in social groups induces: — resorption or abortion in about 50 % of grouped ♀♀, — a high infant mortality (50 % of newborn young), — a significant modification of sex ratio (excess of ♂♂). Finally, the body weight gain is significantly reduced during the first two months of life in offspring of grouped ♀♀.     

Respiratory behaviour of larvae of four species of the Family Polycentropodidae (Trichoptera)

Larvae of Plectrocnemia conspersa and Polycentropus flavomaculatus from flowing water and Cyrnus flavidus and Holocentropus picicornis from still water were selected for study. In the above sequence, these larvae are associated with increasing ranges of temperature in their natural habitats. Experimental determination of lethal temperatures and investigations on ventilation frequency indicated that the larvae were increasingly tolerant of temperature in the same sequence of species. C. flavidus and H. picicornis showed infrequent ventilation which was little affected over wide ranges of temperature and dissolved oxygen but was stimulated erratically by water flow. P. conspersa and P. flavomaculatus showed more active ventilation which was more sensitive to changes in temperature and dissolved oxygen and was decreased by water flow. Consideration of ventilation in relation to oxygen uptake in P. conspersa and P. flavomaculatus suggests that ventilation activity may account for some 60–70% of active oxygen uptake. Differences in ventilation behaviour may thus be important in limiting larval distribution in stream systems.     

Exemples de tératologie chez les Chitinozoaires du Pridoli de Libye et implications sur la signification biologique du groupe

Jaglin, J.-C. & Paris, F. 1992 04 IS: Exemples de tératologie chez les Chitinozoaires du Pridoli de Libye et implications sur la signification biologique du groupe. [Teratologic cases among Pridolian chitinozoans from Libya and implications on the biological interpretation of the group.] Lethaia , Vol. 25, pp. 151–164. Oslo. ISSN 0024–1164.
Fairly numerous chitinozoans displaying morphological anomalies are recorded in Late Silurian subsurface material from Western Libya. The individuals described and illustrated in our paper range exclusively in a short interval at the top of the investigated sequence. These abnormal vesicles are interpreted as teratologic cases related lo an event of unknown origin. From our conclusions, the hypothesis of vegetative reproduction stages stated by previous authors seems unlikely. Therefore we still interpret the chitinozoan vesicles as eggs (or to a lesser extent as spores) of marine organisms. * Libya, Chitinozoans, Silurian, teratology, chitinozoan affinities .