Effect of insect growth regulators on two german cockroach strains and pharaoh ants

When eating poisoned baits based on 0.1–1.0 % pyriproxyfen, within 6 weeks killed up to 50 % of German cockroaches of the S-NIID strain, and 12 % of cockroaches of the OBN strain. The resulting oothecae turned out to be defective and the second generation of cockroaches did not hatch. Morphological changes consisted were in the deformation of the wings (rudimentary, curved, twisted) and in the inability of the larvae to transform into adults. In experiments with an alternative food, similar results were obtained, females formed more oothecae, but the emergence of new generation larvae was not recorded. The consumption of pyriproxyfen-based baits by Pharaoh ant led to the elimination of colonies. A significant decrease in brood number was recorded at 3–6 weeks, and complete death of brood was observed at 6–8 weeks in all treated colonies. The absence of brood can be explained by both mortality as a result of developmental disorders and the cessation of egg laying by queens. Keywords: insect growth regulators, German cockroach, Pharaoh ant, pyriproxifen, hydroprene.

Report on the life history traits of the generalist predatorForficula auricularia(Dermaptera: Forficulidae) in organic apple orchards in southeastern France

The aim of this paper is to provide detailed data on the reproduction of the European earwigForficula auriculariaLinnaeus (Dermaptera: Forficulidae) under natural conditions. We also describe its spring field population structure and dynamics in organic apple orchards in southeastern France using artificial and natural shelters. Two nymph cohorts could be distinguished in a laboratory reproduction study. The first brood, following the first egg-laying event in late November, had significantly higher pre-imaginal survival (1.74-fold) than the second brood in early April. The egg phase was the most vulnerable with a higher mortality rate in the first brood than the second. Independent of brood number, nymphal survival increased from second nymphal instars (N2) onwards with values higher than 96%. In orchards, N3 were generally observed in natural and artificial shelters from the end of April to mid-June. N4 was the most abundant life stage sampled and the only stage present at the majority of sampling dates, especially from early May onwards. Beginning in June, the abundance of new adults of a given year gradually increased especially in the artificial shelters. This descriptive study can now be used to develop phenological models aimed at limiting earwig mortality due to horticultural management practices and increasing their predation level in conservative or augmentative approaches.

Effect of food on growth and fecundity Brine Shrimp Artemia spp. laboratory Conditions

This in order to test the effect of food on growth and fecundity, two kinds of food have been used the algae Scendesmus quadricaudae and fresh water shrimp powder. For two generations, growth and productivity have been followed up. The fresh water shrimp has been noticed as a food better than algae, because it caused recording, for the two generation higher length rate for the weeks of experiment. The individuals length rate at the end of the forth week reached 9.35 and 9.48 mm for the first generation and second generation respectively. The average length weekly increase rate for the first and second generations individuals feeding on dried shrimp was higher through the first and second week compared to what was recorded when feeding algae. The results showed that the fecundity of the individuals feeding on dried better than those feeding on algae. These individuals got matured in about 15 – 18 days old for the first generation and about 16 – 18 days old for the second generation s. Broods number for the two generation was four; the resulting generation was as nuplii larvae. The average number of the generation nauplii was 55.53, 61.20, 16.13 and 57.73 nauplii per mother for the four broads respectively. The average number of the second generation was 56.56,58.10,61.73 and 49.96 nauplii per mother for the four broods respectively . The individual feeding on algae S. quadricaudae recorded length rate of 7.32 and 7.43 for the first and second generation at the end of the forth week . the individuals got matured in about 19-21mm days old for the first generation and about 18-20 days old for the second generation . The first brood appeared in about 25 – 27 days old for the first generation, and about 30 – 35 days old for the second generation. The brood number was two for the first generation, the first one as nauplii larvae with a rate 40.26 larvae per mother and the second as cyst with a rate 27.90 cysts per mother. For the second generation individuals, one brood has been appeared from which the resulting generation was as cysts with a rate of 45.66 cysts per mother.

Reproductive ecology of the velvet swimming crab, Necora puber (Brachyura: Portunidae), at Plymouth

Monthly samples of intertidal and near-shore Necora puber were collected over two years from a commercially unfished area around Plymouth (south-west England). A clear reproductive cycle, consistent between the two years, was observed, and relatively high numbers of ovigerous females were found from January to June. Zoeal release was estimated to occur from April to June. Ovigerous females had developing ovaries, indicating that sequential broods occur. During embryonic development, egg volume increased by 109%, and egg loss was significant, accounting for between 14 and 18.5% of initial brood number. Females suffering limb loss showed a further reduced brood size compared to females with a full limb complement. The sex ratio of immature crabs was 1:1, whereas the ratio for mature crabs was biased to males (1.46:1). Two sperm plugs were observed in 90% of early postmoult mature females, but 10% had only one or no plug intact, suggesting their failure to mate successfully. These results are reviewed in relation to the biogeography of N. puber and with reference to the developing fishery in the United Kingdom.

Dynamique de la population d'Orchestia mediterranea L. (Crustacé, Amphipode) dans l'estuaire du Bou Regreg (Maroc)

Some aspects of the population ecology of Orchestia mediterranea, found in the estuary of Bou Regreg (Morocco), were studied over the course of 1 year. Histograms of cohort frequency and observations on reproductive activity showed seasonal variations all year long: O. mediterranea can be characterized as a multivoltine, semiannual species. By statistical analysis, associated with a procedure near successive maxima, the population structure was determined by identifying cohorts that are associated in a complex manner. All these characteristics are similar to those of O. mediterranea and Talorchestia deshayesei found in the Mediterranean Sea. The exceptionally high annual reproductive potential estimated from the fecundity (which varies with the age of females and with the seasons), the sex ratio, and the brood number of the successive cohorts from the same filiation, all in a nutrient-rich environment, suggests an r type of adaptative strategy.