瑞香狼毒浸提液杀虫效果研究

以采于吉林省白城地区瑞香狼毒提取液为供试药剂,以小菜蛾,蚜虫,菜青虫,土蝗为供试昆虫．将瑞香狼毒分别用蒸馏水、乙醇、丙酮溶剂浸泡提取,通过对试验昆虫定时喷洒不同种类的瑞香狼毒提取液．观察并记录24h、48h、72h内,供试昆虫的死亡数量．通过供试昆虫对瑞香狼毒不同浸提液的敏感程度,来研究瑞香狼毒提取液的杀虫活性,以确定瑞香狼毒在病虫害防治方面的生物效应．     

Relation between plant density and arthropod density in cabbage fields

The relationship between plant density and the abundance of arthropods was examined by planting cabbages in four densities (0.25, 1, 4, or 8 plants per square meter). Four herbivorous species were examined: the small white butterfly Pieris rapae crucivora Boisduval, the diamondback moth Plutella xylostella (Linnaeus), the beet semi-looper Autographa nigrisigna (Walker), and the green peach aphid Myzus persicae (Sulzer). The number of spiders and the number of eggs of syrphid flies were also examined. The number of individuals per unit ground area increased curvilinearly with increasing plant density for most arthropods. To clarify the mechanism causing such a curvilinear increase, the oviposition behavior of Pieris rapae crucivora was examined. The oviposition process of a female was divided into three components: (1) entering the field, (2) alighting on a plant to bend her abdomen, and (3) attaching an egg on the leaf. The first and the second components curvilinearly increased with increasing plant density, while the third component was not influenced by the plant density. The analysis of the flight path of P. rapae crucivora indicated that the curvilinear increase in the frequency of abdominal bending behaviors occurs since a female flies at least about 1.3 m between successive abdominal bending behaviors, irrespective of the plant density, when the plant density is sufficiently high. Received: October 23, 1998 / Accepted: February 15, 1999     

Male mating behavior in relation to spermatophore transfer in the white cabbage butterfly

The lifetime mating frequency of female butterflies is believed tobe dependent on the reproductive status of the males which they have mated. This report assesses those status usingPieris rapae L. Multiple mating females mated males with a short time interval after the last mating or males with many mating records. Such males, like small ones, produced small spermatophores during copulation, which may have resulted in high mating frequency of those females. The males with short time interval after the last mating or those with many mating records also showed a long mating duration. Alternative interpretations of the adaptive significance of this behavior for males are discussed.     

Warning coloration in sawflyAthalia rosae larva and concealing coloration in butterflyPieris rapae larva feeding on similar plants evolved through individual selection

Summary Green larvae of the butterflyPieris rapae and black larvae of the sawflyAthalia rosae feed on green leaves of the same cruciferous plants. To demonstrate thatP. rapae has concealing coloration and thatA. rosae has warning coloration, the larvae of the two species were supplied to naive chicksGallus gallus on white, green or black backgrounds.P. rapae larvae were palatable and their green body color acted as a concealing coloration. On the other hand,A. rosae larvae were unpalatable and their black body color acted as a warning coloration. There is a general consensus that warning coloration is an altruistic character which needs victims, and thus can evolve through kin selection or green beard selection. However, blackA. rosae larvae were seldom injured by chicks' attack, in particular, on the green background. Therefore, the warning coloration ofA. rosae larvae can be a selfish character and hence can evolve through individual selection as well as concealing coloration ofP. rapae.     

Heritability estimates of life history traits in small white butterflyPieris rapae crucivora

Summary Heritabilities and genetic correlations of life history characters (pupal weight, age-specific fecundities, and egg weight) of small white butterflyPieris rapae crucivora are estimated by a quantitative genetic method (sib analysis). The results indicate moderate or high heritabilities and a largely negative genetic correaltion in age-specific fecundities.     

胡桃楸果实提取液杀虫效果研究

以采于吉林省长白山实验室提取胡桃楸果实提取液为供试药剂,以十字花科蔬菜害虫小菜蛾,落叶松鞘蛾幼虫,菜青虫,土蝗为供试昆虫。对胡桃楸果实提取液的杀虫活性进行了研究,以确定它们在病虫害防治方面的生物效益。     

The learning abilities of the white cabbage butterfly,Pieris rapae, foraging for flowers

This study examines the role of learning and memory in the butterflyPieris rapae crucivora Boisduval during foraging for flowers. In an outdoor cage with 6 flower species,P. rapae showed various visiting patterns: some visited only one species, while others visited several species in a day. The foraging process for flowers ofErigeron annuus (L.) Pers. could be divided into two successive steps: (1) landing on the nectaring caputs, and (2) finding the source of nectar in the caput. Butterflies learned to proceed through the two steps more efficiently with successive attempts: they gradually decreased landings on nectarless caputs and probings on the nectarless petals of ligulate flowers respectively. As a result, handling time per unit caputs became shorter, and apparent rewards per unit time, i.e. the efficiency of collecting nectar, increased. In addition, once learned,P. rapae could remember a rewarding flower color for 3 days, which was not interfered with by learning another flower color. This indicates thatP. rapae keeps memory for a period longer than 3 days, and that they can remember at least two flower species as suitable flower resources. Furthermore, data indicated that they sometimes can apply the foraging skills obtained on other flower species to a novel one. These abilities could enable butterflies to easily switch flower species, or to enhance labile preference. It has been known thatP. rapae also shows flower constancy, which may be due to memory constraints. Therefore, they may appropriately use two foraging tactics: visit consistency and labile preference, to get enough nectar according to their circumstances.