We investigated the variation in body colour and its thermoregulatory function in Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), a parasitoid wasp of Spodoptera and other free-living lepidopteran larvae. We show that the body colour of adult wasps darkens when cocoons are kept at low temperatures. The range in the variation in colour, however, differs for different parts of the body and among uniparental (thelytokous) strains. This melanism enables these wasps to attain a body temperature in sunshine up to 2°C. Moreover, this small gain in body temperature can markedly increase the flight activity of wasps at low ambient temperatures. We conclude that the variation in body colour that resulted from rearing the cocoons at different temperatures enable the wasps to adapt to changing thermal environments. The ecological significance of the difference in the degree of melanism of the different strains is discussed., Yosuke Abe, Takuma Nishimura, Kaoru Maeto., and Seznam literatury
Ecological studies on the buprestid beetle Capnodis tenebrionis (Linnaeus, 1767) were carried out in the laboratory and the field. In particular, attention focussed on the effects of seven different temperatures at different times during the day on the movement and feeding activity of this beetle. Field experiments in an apricot orchard recorded the flight activity of C. tenebrionis, with particular reference to the effect of temperature and wind. The experiments highlighted the marked response of movement, feeding and flight activity to increase in temperature. The optimal temperature for feeding, movement and flight was 30°C and above with negative effects occurring at 45°C. Flight generally occurred in the middle of the day. Wind had a negative effect on flight activity. Wind speeds in excess of 4 m/s prevented the insect from taking off. The spread of this phytophagous beetle from one orchard to another is unquestionably influenced by the daily activity and flight behaviour of the adult.
The responses of females of the water strider, Aquarius paludum, to changes in NaCl concentration were examined in the laboratory. The insects were sampled seasonally in 2002 and 2003 at two reservoirs in Kochi, Japan, connected by a waterway, one at the mouth of the river with high NaCl concentrations (the range in NaCl concentration during a year: 0.1-1.08%) and one 700 m upstream, where the salinity was lower (0.03-0.23%). Sudden increase in NaCl concentration, from 0.45 to 0.9%, after adult strider emergence suppressed reproduction and promoted flight activity, whereas a decrease in salinity did not affect either trait. In the field, A. paludum was univoltine in brackish and multivoltine in freshwater ponds. Thus, the number of breeding periods per year was limited by fluctuations in the NaCl concentration in brackish habitats. Our results suggest that A. paludum can breed in brackish waters when the NaCl concentration is below the limitation for reproduction and growth. Abrupt increases in NaCl concentration caused by seawater surges, such as those following typhoons, can trigger the migration of individuals, which move to areas of lower NaCl concentration and so mix the genes of individuals inhabiting brackish and freshwater bodies.
Flight activity in a pentatomid bug, Graphosoma lineatum, was measured under different photoperiodic conditions. Insects started flying 3 days after adult ecdysis and the percentage of flying adults became highest about 1 week after the ecdysis, regardless of the photoperiod. Under long day (18L : 6D), high flight activity was continued, whereas under short day (12L : 12D), most adults stopped flying when diapause was induced. In both photoperiods, a small number of adults showed flight of a long duration, longer than 30 minutes. Thus, no evidence was found relating the long flight to diapause. It is suggested that diapause adults of G. lineatum do not overwinter far from their breeding sites and thus there is no migration to hibernation sites. Also, the long flight is probably only a foraging flight, enabling the bugs to find their dispersed host plants.
Flea beetles are characterized by their tendency to jump. They can also fly. First, the effects of starvation on flight activity in the flea beetle, Phyllotreta nemorum L. (Coleoptera: Chrysomelidae) were determined. After starving P. nemorum for five days a greater number of individuals of both sexes flew than when fed continuously for the same period. In addition, the effect of the mating status of females of P. nemorum on their movement was determined. Mated females were more active than virgin females. It is concluded that starvation stimulates the flight activity of both sexes and mating activates the movement of females of P. nemorum.
The aim of our study was to assess the seasonal and overnight changes in the flight activity and habitat use of four bat species under the conditions of a sub-mountain town by a detector monitoring. The urban habitats visited from May untill October 1998 – 2000 were divided into three categories: gardens (illuminated or non-illuminated gardens and larger groups of trees), urban habitat (old and new buildings in suburbs and downtown), and water (streams and ponds). Only for Myotis daubentonii was a statistically significant increase in flight activity recorded between the lactation and post-lactation periods. The highest activity of M. daubentonii was recorded in the vicinity of water bodies. The activities of Pipistrellus pipistrellus and Nyctalus noctula were similar in relation to the habitats. Only in Eptesicus serotinus was the activity recorded per habitat type not significantly different. The changes of activity of P. pipistrellus had a bimodal character with the first peak in the 5th and the 6th ten-minutes and the second in the 12th ten-minutes. In N. noctula, activity was characterized by commuting over the urban habitats during the first 0.5 h. Relatively high activity was recorded in E. serotinus during the first 0.5 h in gardens.