Dispersion or dilution of stool by water from heavy rainfall may affect Strongyloides stercoralis free-living development producing infective filariform larvae (FL). This study examined effect of water dilution of stool on survival of S. stercoralis free-living development. One g of stool was prepared in water so that its soluble component was diluted sequentially from 1:2 to 1:480. Three dishe...

Free-living ixodid ticks were collected at monthly intervals from January to December 1996 by dragsampling the vegetation of Mtendere Game Ranch in the Chisamba District of the Central Province, Zambia. Ticks belonging to 11 species were recovered. Rhipicephalus appendiculatus was most abundant, comprising 90% of the total number collected. All life stages of this tick showed a definite seasona...

Flooding exposes terrestrial organisms to severe hypoxia. Among the best-studied insects that are frequently exposed to ßooding are tiger beetle (Coleoptera: Cicindelidae) larvae. In previous studieswitha limitednumberof species, a correlationwas foundbetweenhabitat andhypoxia tolerance. In the current study, we examined hypoxia tolerance among third instars of six Cicindela species that vary i...

1. Dry weight, body length and spine length were measured for the exotic cladoceran Bythotrephes cederstroemii collected from offshore and inshore stations in southeastem Lake Michigan. Average dry weight of each developmental stage exhibited seasonal variation by a factor of more than 5. 2. Mean dry weight of Bythotrephes was closely correlated with water temperature. Contrary to the inverse r...

Seasonal fluctuations in mean dry weight of the copepod Calanus helgolandicus were large and contrasted markedly with the small seasonal fluctuations of cephalothorax length. Dry weight was related linearly to cephalothorax length on logarithmic axes by a series of regression equations which were significantly different for each of 8 cruises. Carbon and nitrogen were likewise linearly related t...

Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrol...

Decreased larval feeding and weight of the monarch butterfly, Danaus plexippus L., have been detected after 4 d of exposure in the laboratory to a high density of Bacillus thuringiensis (Bt)-expressing anthers. One hypothesis is that larvae exposed to Bt anthers exhibit increased wandering, resulting in less feeding and lower weight gain. To test this hypothesis, 2-d-old monarch butterfly larva...

This study aimed to evaluate the feeding responses and digestive proteolytic and amylolytic activity of Helicoverpa armigera (Hübner) on 11 corn (Zea mays L.) hybrids at 25 ± 1°C, 65 ± 5% relative humidity (RH), and a photoperiod of 16:8 (L:D) h. The fourth- and fifth-instar larvae fed on hybrid K47*K19 had the highest weight of food consumption and those reared on hybrid KSC705 had the lowest ...

Secondary microbial invasion of tomato plants inoculated with 6,000 Meloidogyne incognita larvae caused 75 and 48% weight reduction of foliage and roots, respectively. Under aseptic conditions the same number of larvae caused only 37% reduction of foliage and increased root weight by 50%.

Leaf bioassays and oviposition choice tests were used to investigate the effects of transgenic broccoli expressing Cry1Ac toxin of Bacillus thuringiensis (Berliner) on susceptible and resistant Plutella xylostella (L.) larvae. Survival of susceptible 2nd instars on Cry1Ac-expressing broccoli declined from 99.1 to 19.2% at 24 and 72 h, respectively, and larvae exhibited an average weight loss of...