Long-term within pond variation of egg deposition sites in the agile frog, <Emphasis Type="Italic">Rana dalmatina</Emphasis>

This study presents long-term fluctuation, within pond distribution and mortality of egg masses in a population of Rana dalmatina reproducing in a permanent semi-natural pond in Romania. The average number of egg masses per year was 410 (SD = 114.56, min.-max. = 265–581). The mean spawning duration (days) was 26.72 (SD = 5.53). The egg mass distribution was not constant during the years. The long-term change in the distribution of egg masses can be related to changes in the reed cover (pond variable) and landscape structure, i.e. the presence of the forest and a pasture between the pond and the forest. There was a reduction in the number of dead egg masses during the study period. We suggest that the maintenance of the connectivity with the forest and the variable amount of reed assure the main aquatic and terrestrial habitats for the agile frogs. This will allow agile frogs to shift breeding habitats in this area according to their ecological needs and find safe terrestrial habitats for summering and wintering.     

The presence of knockdown resistance mutations reduces male mating competitiveness in the major arbovirus vector,Aedes aegypti

BackgroundThe development of insecticide resistance in mosquitoes can have pleiotropic effects on key behaviours such as mating competition and host-location. Documenting these effects is crucial for understanding the dynamics and costs of insecticide resistance and may give researchers an evidence base for promoting vector control programs that aim to restore or conserve insecticide susceptibility.Methods and findingsWe evaluated changes in behaviour in a backcrossed strain of Aedes aegypti, homozygous for two knockdown resistance (kdr) mutations (V1016G and S989P) isolated in an otherwise fully susceptible genetic background. We compared biting activity, host location behaviours, wing beat frequency (WBF) and mating competition between the backcrossed strain, and the fully susceptible and resistant parental strains from which it was derived. The presence of the homozygous kdr mutations did not have significant effects on blood avidity, the time to locate a host, or WBF in females. There was, however, a significant reduction in mean WBF in males and a significant reduction in estimated male mating success (17.3%), associated with the isolated kdr genotype.ConclusionsOur results demonstrate a cost of insecticide resistance associated with an isolated kdr genotype and manifest as a reduction in male mating success. While there was no recorded difference in WBF between the females of our strains, the significant reduction in male WBF recorded in our backcrossed strain might contribute to mate-recognition and mating disruption. These consequences of resistance evolution, especially when combined with other pleiotropic fitness costs that have been previously described, may encourage reversion to susceptibility in the absence of insecticide selection pressures. This offers justification for the implementation of insecticide resistance management strategies based on the rotation or alternation of different insecticide classes in space and time.     

A revision of Atlantic species of Photostomias (Teleostei: Stomiidae: Malacosteinae), with a description of a new species

While one or possibly two species of the genus Photostomias have been recognized, an unpublished revision of the Malacosteinae suggested that there may be as many as six species worldwide. Our review of museum material revealed three taxa in the Atlantic alone: Photostomias atrox Alcock, 1890; Photostomias guernei Collett, 1889; and a new species described herein. Because of a paucity of Indo-Pacific material and a need to better document Atlantic biodiversity, we treat only the Atlantic species at this time. A key to the identification of Atlantic Photostomias is given.     

Oestrus synchronization in sheep with progesterone-impregnated (MAP) intravaginal sponges and a prostagland in analogue

A double injection of PGF2α at two different dosage levels, 5 mg and 10 mg, eleven days apart, were compared with a combination of MAP-sponges and 5 mg or 10 mg PGF2α.The combination of MAP-sponges plus 10 mg PGF2α gave the best syn=chronization results (93,4%), as well as the best conception rate (84,9%) when ewes were inseminated on a fixed time basis 68 and 80 hours after treatment.