Effects of protein type and concentration on development and reproduction of the German cockroach, Blattella germanica

Nymphal development and adult female reproduction were examined in the German cockroach, Blattella germanica, using a defined artificial diet in which the type of protein was varied. Milk proteins, including casein, supported development poorly compared to meat and plant proteins. Soybean protein supported development better than all other highly purified proteins including vitamin-free casein which is commonly used in artificial diets. Last instar females fed the soybean-based diet eclosed earlier at higher eclosion weights, developed their oocytes at a faster rate and experienced higher fecundity than females fed a vitamin-free casein-based diet. Last instar females exhibited different dose-response patterns on diets containing soybean isolate or vitamin-free casein. However, at all concentrations soybean protein was superior to casein in supporting development. The results of a food utilization study during the last instar revealed that consumption rates varied between females fed the soybean and casein based diets. However, approximate digestibility, efficiency of conversion of digested food and the efficiency of conversion of ingested food did not vary significantly between the two dietary treatments. Differential development of females fed the two diets was attributed to differences in stage-specific consumption rates and the poorer quality of casein as a source of protein for development in this species.     

Qualitative and quantitative variation of tRNA in certain invertebrates

Total tRNA was isolated, purified and quantitated from earthworm, cockroach, fresh water mussel and rat liver. The total tRNA content of invertebrates was found to be much lower than that of rat liver. When checked for aminoacylation capacity with homologous and heterologous enzymes and algal protein hydrolysate, the tRNA preparation from rat liver and fresh water mussel, a mollusc, were found to be active. On the other hand, the tRNAs from earthworm, an annelid, and cockroach, an arthropod, were completely inactive with the homologous enzymes but showed partial activity with heterologous enzymes. Similar results were obtained with individual amino acids also. The low activity or inactivity of earthworm and cockroach tRNAs appears to be due to certain endogenous aminoacylation inhibitors. This work was carried out at the School of Life Sciences, University of Hyderabad, Hyderabad 500 134, India.     

Overwintering colonies of German (Vespula germanica) and common wasps (Vespula vulgaris) (Hymenoptera: Vespidae) in New Zealand

Abstract

Nests of both common (Vespula vulgaris) and German wasps (V. germanica) sometimes overwinter in New Zealand. Three overwintering common wasp colonies were found in low-altitude honeydew beech forest; about 2% of the colonies initiated there in 1988 survived the winter. Wasp traffic rates from nests in Nelson city and a nation wide survey of wasp abundance, showed that more German wasp than common wasp workers were on the wing in winter and spring. German wasp colonies in Nelson city were more likely to overwinter than were common wasp colonies. Of the active German wasp colonies recorded in Nelson in January and February 1989, only two (4%) had previously overwintered, but these two nests accounted for 38% of all German wasp workers estimated to leave nests in the area. Had other overwintering colonies not been poisoned, overwintering colonies might have accounted for up to 11 % of nests and produced up to 64% of German wasp workers on the wing in January and February 1989.

Overwintering common wasp colonies did not produce queens or drones in their first year or second spring, but all 10 overwintering German wasp colonies examined produced sexuals at both times. German wasp queens produced in winter and spring may influence the number of colonies successfully initiated and affect the population dynamics of German wasps in New Zealand.     

Persistence and effects of α-methyl-substituted amino acids on 5-hydroxytryptamine and dopamine concentrations in cockroach (Periplaneta americana) nervous tissue

The α-methylated derivatives of tryptophan, tyrosine, and dihydroxyphenylalanine were injected into cockroaches (Periplaneta americana). The levels of these compounds and those of dopamine, 5-hydroxytryptamine, tyrosine, and tryptophan in the nervous tissue, hemolymph, and fat body were measured at various times after drug administration. Levels of 5-hydroxytryptamine and tryptophan in the nervous tissue are significantly reduced by α-methyltryptophan administration. Concentrations of dopamine in nervous tissue are reduced by α-methyltyrosine administration. This effect also persists for several weeks, and α-methyltyrosine is observed in the nervous tissue 3 weeks after injection. Levels of dopamine and 5-hydroxytryptamine in the nervous tissue are unaffected by α-methyldihydroxyphenylalanine, and this compound is less persistent in nervous tissue than α-methyltyrosine or α-methyltryptophan demonstrates that these compounds can be absorbed and affect amine levels in the nervous tissue when included in the diet. Inhibition of tryptophan hydroxylation by crude enzyme preparations of cockroach nervous tissue was demonstrated with both α-methyltryptophan and α-methyltyrosine, with α-methyltryptophan being the more effective inhibitor. Aromatic amino acid decarboxylase activity toward dihydroxyphenylalanine in crude enzyme preparations of cockroach nervous tissue was strongly inhibited by α-methyldihydroxyphenylalanine and monofluoromethyldihydroxyphenylalanine, slightly inhibited by α-methyltyrosine and unaffected by α-methyltryptophan at concentrations up to 10^?3 M. The results indicate that α-methyltyrosine and α-methyltryptophan, but not α-methyldihydroxyphenylalanine, can selectively alter amine concentrations in insect nervous tissue and that insects are only poorly able to metabolize or excrete these compounds. The selective and long-lasting depletion of dopamine or 5-hydroxytryptamine by some of these compounds suggest that they may be useful in behavioral studies designed to elucidate the roles of these amines in insects.     

Immunocytochemical localization of sodium channels in an insect central nervous system using a site-directed antibody

Antibodies to channel proteins and specific peptide sequences have been previously used to localize voltage-activated sodium channels in the rat brain. Here we describe the first localization of sodium channels in an insect nervous system using a site-directed antibody. The mesothoracic ganglion of the cockroach was stained with an antibody to the highly conserved SP19 sequence. Antibody labelling was visualized by light microscopy using the avidin/biotin method on was sections, and transmission electron microscopy of immunogold-labelled thin sections. Central ganglia of insects contain clearly separated regions of cell bodies, synaptic neuropil, axon tracts, and nerves. Antibody staining by light microscopy was limited to neurons, and was intense in axons throughout the ganglion and nerves. Staining was also strong in the cytoplasm, but not the nuclei, of many neuronal cell bodies. Neuropil regions were relatively lightly labelled. These findings can be correlated with the known electrophysiology of the ganglion. Electron microscopy detected sodium channels in areas surrounding axons, probably including axon membranes and enveloping glial cell membranes. Axonal mitochondria were also heavily labelled, suggesting a sodium channel transport function for these organelles. © 1993 John Wiley & Sons, Inc.     

Reproductive and developmental biology of the oriental cockroach Blatta orientalis (Dictyoptera)

At 27 degrees C and 45% r.h. in the laboratory, the oriental cockroach Blatta orientalis (L.) developed to adulthood in seven to nine instars for males (66% had eight instars) and eight to ten instars for females (67% had nine instars) in mixed groups, with up to twelve instars for isolated females. Nymphal development lasted 185 +/- 2 days for males, 216 +/- 4 days for females, with 89% survival to adulthood. Adult longevity was significantly more for males than females in mixed groups. Virgin females lived for 135 +/- 6 days compared with 87 +/- 9 days for females kept with males. After an initial maturation time of 12.2-13.5 +/- 0.4 days for mated and unmated females, oothecae were produced, on average, every 6-7 (range 2-29) days. Ootheca viability was 68% from females kept with males, 32% from females kept apart from males. Numbers of nymphs emerging were 14.1 +/- 0.26 after 45 days from mated female oothecae 8.2 +/- 0.3 after 49 days from unmated females. With sexual reproduction the sex ratio of progeny reaching adulthood was 1.1 males per female (n = 443), whereas unmated females produced only female progency, which is consistent with parthenogenetic reproduction. Drawings of the ventral aspect of the terminalia are given to show features useful for instar determination and for distinguishing between male and female nymphs and adults of B. orientalis.     

A revision of the genus Arenivaga (Rehn) (Blattodea,Corydiidae), with descriptions of new species and key to the males of the genus

The cockroach genus Arenivaga is revised. Forty-eight Arenivaga species are recognized with nine previously known species and 39 described as new including the following: A. pagana sp. n., A. grandiscanyonensis sp. n., A. haringtoni sp. n., A. hopkinsorum sp. n., A. umbratilis sp. n., A. tenax sp. n., A. impensa sp. n., A. trypheros sp. n., A. darwini sp. n., A. nalepae sp. n., A. sequoia sp. n., A. mckittrickae sp. n., A. gaiophanes sp. n., A. belli sp. n., A. estelleae sp. n., A. delicata sp. n., A. mortisvallisensis sp. n., A. milleri sp. n., A. pratchetti sp. n., A. gumperzae sp. n., A. rothi sp. n., A. ricei sp. n., A. adamsi sp. n., A. nicklei sp. n., A. akanthikos sp. n., A. moctezuma sp. n., A. paradoxa sp. n., A. apaeninsula sp. n., A. hebardi sp. n., A. dnopheros sp. n., A. aquila sp. n., A. florilega sp. n., A. galeana sp. n., A. gurneyi sp. n., A. pumila sp. n., A. hypogaios sp. n., A. diaphana sp. n., A. nocturna sp. n., A. alichenas sp. n. All species are described or redescribed, major morphological features are illustrated, distributions are characterized, and the biology of the species is reviewed. A neotype series is designated for A. investigata Friauf & Edney.     

Cold winter effects on benthic macrofauna communities in near- and offshore regions of the North Sea

In order to investigate the effect of severe winters on the long-term variability of benthic macrofauna communities four stations from the inner German Bight towards the Dogger Bank (North Sea) were sampled in March 1990 and from May 1995 to 2002. The stations were chosen to reflect a gradient in the hydrographic regime, temperature and organic matter supply. We initially hypothesized that the effect of severe winters on benthic communities will be more pronounced in the offshore more stable environment than in the nearshore regions. Our results clearly showed the opposite pattern. The benthic communities at the nearshore stations in the German Bight changed dramatically in species abundance and community structure after the severe winter 1995/1996. But the community structure in the German Bight returned to the previous stage within 2 years. In contrast, the offshore stations in the Oyster Ground and at the Dogger Bank remained rather unaffected by the severe winter and changed gradually during the study period. The results are discussed concerning the ecological importance of severe winters for benthic communities and the utility of our results for interpreting long-term changes.