Lepidoptera genitalia

About: Lepidoptera genitalia is a research topic. Over the lifetime, 10114 publications have been published within this topic receiving 78876 citations. The topic is also known as: Uncus.

Genetic Variation for Resistance to Bacillus thuringiensis Toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in Eastern North Carolina

Abstract: To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 μg/ml Cry1Ac toxin, or diet containing 5.0 μg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).

Recent shifts in phenology of Microlepidoptera, related to climatic change (Lepidoptera)

Abstract: One of the many effects of the warming of the global climate that have been predicted is an acceleration of the larval development of insects. Insect populations living in temperate climates generally have one or more generations per year, punctuated by the winter resting period. We hypothesised that a gradual shift in the timing of these generations to¬ wards an earlier date will take place. For this purpose we analysed the phenology of a large sample of the most common Microlepidoptera in The Netherlands. Our results show that during the period 1975 1994 the flight peak has shifted to a date 11.6 days on average earlier. This shift is primarily associated with a rise in spring temperatures. The phenological data are based on a large body of observations brought together at little cost by amateur recorders, and the results sug¬ gest a relatively inexpensive method of monitoring future climatic change. Tinea foundation, Institute of Systematics and Population Biology, University of Amsterdam, Plantage Middenlaan 64, 1018 DH Amsterdam, The Netherlands.

Nitrogen enrichment in host plants increases the mortality of common Lepidoptera species

Abstract: The recent decline of Lepidoptera species strongly correlates with the increasing intensification of agriculture in Western and Central Europe. However, the effects of changed host-plant quality through agricultural fertilization on this insect group remain largely unexplored. For this reason, we tested the response of six common butterfly and moth species to host-plant fertilization using fertilizer quantities usually applied in agriculture. The larvae of the study species Coenonympha pamphilus, Lycaena phlaeas, Lycaena tityrus, Pararge aegeria, Rivula sericealis and Timandra comae were distributed according to a split-brood design to three host-plant treatments comprising one control treatment without fertilization and two fertilization treatments with an input of 150 and 300 kg N ha−1 year−1, respectively. In L. tityrus, we used two additional fertilization treatments with an input of 30 and 90 kg N ha−1 year−1, respectively. Fertilization increased the nitrogen concentration of both host-plant species, Rumex acetosella and Poa pratensis, and decreased the survival of larvae in all six Lepidoptera species by at least one-third, without clear differences between sorrel- and grass-feeding species. The declining survival rate in all species contradicts the well-accepted nitrogen-limitation hypothesis, which predicts a positive response in species performance to dietary nitrogen content. In contrast, this study presents the first evidence that current fertilization quantities in agriculture exceed the physiological tolerance of common Lepidoptera species. Our results suggest that (1) the negative effect of plant fertilization on Lepidoptera has previously been underestimated and (2) that it contributes to the range-wide decline of Lepidoptera.