Parasitism and decreased response to sex pheromones in malePeriplaneta americana (Dictyoptera: Blattidae)

Parasites are known to alter the behavior of their hosts, but little is known about their effects on responses to sexual stimuli. Periplaneta americanainfected with the acanthocephalan Moniliformis moniliformiswere compared to uninfected animals in their behavioral and electroantennogram responses to a synthetic P. americanapheromone component, periplanone-B, and a pheromone mimic, bornyl acetate. In a t-maze there was no significant difference between infected animals' responses to periplanone-B and a random binomial distribution; the responses of uninfected animals were significantly nonrandom. The electroan-tennogram responses of infected and uninfected animals to bornyl acetate or periplanone-B did not differ significantly, however, indicating that the alteration probably does not occur at the peripheral level but at a central nervous system level.     

Cockroach mating behaviors,sex pheromones,and abdominal glands (Dictyoptera: Blaberidae)

Two chemical signals are essential in all cockroach sexual behavioral sequences: the sex pheromone released by one partner, generally the female (for long distance attraction), and an aphrodisiac sex pheromone produced exclusively by male tergal glands (for female mounting and tergal contact or feeding behavior). Unlike the other cockroach groups, the males of the Oxyhaloinae species produce both chemical signals: the pheromone and the aphrodisiac. The occurrence of three patterns of mating behavior (A, B, and C), the production of male sex pheromones, and the existence in the male of developed sternal and tergal glands in seven related Oxyhaloinae species, make these cockroaches a useful model for studying the evolution of mating behavior patterns. The various types of mating behavior were not classified in the previous studies by Roth and Barth. In this report, they have been named type A (female in upper position), B (male in upper position), and C (male and female end to end). In type A mating, the male tergal glands, which are licked by the females, are well developed, whereas in types B and C, there is no licking of the male's tergal secretion by the females and the tergal glands are much less developed; the aphrodisiacs secreted by the tergal glands may no longer act in this case through contact chemoreception, but through an olfactory process involving volatile components. One common sex pheromone component seems to be acetoin. I suggest that the mating behavior tends from A toward B and C during the evolutionary process with a concomitant regression of the tergal glands and changes in the aphrodisiac emission levels. The mating behavioral sequences of cockroaches (Dictyoptera) and crickets (Orthoptera) show a striking degree of similarity and are probably examples of convergent evolution.     

Factors influencing the effectiveness of an attracticide formulation against the Oriental fruit moth, Grapholita molesta

An attracticide formulation, LastCall?OFM, was tested against the Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in replicated small plot field trials in apple, Malus domestica (Borkhausen), orchards in South‐eastern Pennsylvania, USA. Attracticide treatments were applied using a calibrated hand pump, and treated plots were compared to similar untreated plots. Male moth activity was monitored using virgin female‐baited traps, and the potential for reduction in mating activity was assessed using sentinel virgin females. A comparison of application rates showed that 1500 droplets per ha of the attracticide formulation was as effective as 3000 droplets per ha, and both application rates reduced captures in synthetic pheromone‐baited traps for prolonged periods. Droplets placed either at high or low positions within the canopy significantly reduced trap capture and mating with sentinel females. In addition, the only sentinel females that mated in the treated plots were located in the untreated portion of the tree canopy. Mate finding behaviour was equally disrupted by formulations with and without insecticide. Therefore, under the test conditions, the mechanism by which the attracticide formulation worked was by disruption of male orientation, and not by the removal of males due to insecticide poisoning. Two field cage experiments tested the impact of population density on the competitiveness of the attracticide formulation compared to virgin females. A significant proportion of males were captured in female‐baited traps at the highest female‐to‐droplet ratio tested. Equal proportions of males were captured in attracticide‐baited traps at male moth densities of 10, 20, 40, and 80 males per cage. These results clarify some of the factors influencing the effectiveness and possible mechanisms of an attracticide management tactic against the Oriental fruit moth.     

The sublethal effects of tebufenozide on the precopulatory and copulatory activities of Choristoneura fumiferana and C. rosaceana

The sublethal effects of tebufenozide, an ecdysone agonist, on the reproductive biology of Choristoneura fumiferana (Clem) and of Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), treated during the larval stage, were evaluated using two treatment methods: the force‐feeding method and the diet method. The percentage of mortality and the developmental time of survivors increased linearly with the concentration of tebufenozide used. This ecdysone analogue proved to be more toxic to C. fumiferana than to C. rosaceana. In C. rosaceana, the weight of males and females decreased proportionally with the dose ingested, but females were affected to a greater extent. This difference might be due to a greater consumption of the treated diet, or to a differential vulnerability to tebufenozide. Tebufenozide did not modify the pre‐copulatory activities associated with chemical communication in the females. However, the consumption of tebufenozide delayed ovarian maturation, causing a reduction in the fecundity of females. Treated males had smaller spermatophores and fewer eupyrene sperms in their bursa copulatrix and spermatheca, along with lower mating success. In C. fumiferana, tebufenozide delayed the females’ onset time of calling the first night after emergence, but did not affect the mean time spent calling or the production of the main component of the sex pheromone. The males showed significantly greater difficulty in executing oriented flight in a wind tunnel, although their mating success was not affected. We concluded that tebufenozide interferes with various aspects of the reproductive biology of males and females of C. fumiferana and C. rosaceana, including some pre‐copulatory behaviors associated with sex pheromone communication.     

Molecular cloning of pheromone biosynthesis activating neuropeptide in silkworm, Bombyx mori

Pheromone biosynthesis activating neuropeptide (PBAN) is a suboesophageal ganglion secretory polypeptide of insect, which activates the pheromone gland to produce sex pheromone biosynthesis in female silkworm, Bombyx mori. A Bombyx genomic library was screened by the method of plaque hybridization using the 32P-labeled BomDH cDNA as a probe. The genomic sequence encoding PBAN has been cloned and its structure is analyzed. The PBAN gene comprises two exons interspersed by a single intron 697 bp in length. Preceding the PBAN amino acid sequence is a 32-amino acid sequence containing two FXPRL amide peptides, which are α-SGNP (Ile-Ile-Phe-Thr-Pro-Lys-Leu) and β-SGNP (Ser-Val-Ala-Asn-Pro-Arg-Thr-His-Glu-Ser-Leu-Glu-Phe-Ile-Pro-Arg-Leu), which is followed by a Gly-Arg processing site. Immediately, after the PBAN amino acid sequence is a Gly-Arg processing site and a FXPRL amide peptide γ-SGNP (Thr-Met-Ser-Phe-Ser-Pro-Arg-Leu). It is suggested that besides PBAN, 7-, 8-, and 17-residue amidated peptides wer     

Absence of chemical alarm in a primitively eusocial wasp (Belonogaster petiolata,Hymenoptera: Vespidae)

Summary The hypothesis thatBelonogaster petiolata (fam. Vespidae) is able to communicate alarm chemically, using odours released with the venom, was tested in bioassays involving presentation of artificial targets to a wasp colony, simultaneously with crushed venom apparatuses. The odour of venom did not lower the threshold of attack and visual stimuli alone (particularly a black, moving object) were sufficient to release attack. Venom odour on a previously stung target probably does not play a role in focusing further attacks on such a target. The results therefore support the null hypothesis that a venom-based alarm pheromone is absent in this species.     

昆虫神经肽研究进展

近年来鉴定了化学结构的昆虫神经肽数目呈快速上升趋势, 家蚕滞育激素和性信息素合成激活肽被分离纯化.三种近年出现的研究方法对寻找新型昆虫神经肽起到重要作用,已经成功地鉴定了数个新型神经肽.昆虫神经肽cDNA或基因组DNA克隆显示了新的结构信息和神经肽间的相互关系.     

马尾松毛虫雄蛾触角毛状感受器的细微结构

马尾松毛虫Dendrolimus punctagus(Walker)雄蛾有一对羽毛状触角。在触角鞭节的每对侧枝的内侧(迎风面)着生许多毛状感受器。每个毛状感受器由几丁质表皮毛及位于其下的三个感觉神经原和三个呈同心排列的辅助细胞-鞘原细胞、毛原细胞和膜原细胞构成。几丁质表皮毛上有许多孔。毛腔内充满感受器淋巴液。感觉神经原发出的树状突伸入毛腔,浸浴于感受器淋巴液内。这些结构特征表明它是一种司嗅觉的化学感受器。雄蛾终生不取食,推断它的嗅觉感受器主要用以感受雌蛾释放的性外激素,帮助寻找配偶。     

马尾松毛虫雄蛾触角毛状感受器的细微结构

马尾松毛虫Ｄｅｎｄｒｏｌｉｍｕｓｐｕｎｃｔａｔｕｓ（Ｗａｌｋｅｒ）雄蛾有一对羽毛状触角。在触角鞭节的每对侧枝的内侧（迎风面）着生许多毛状感受器。每个毛状感受器由几丁质表皮毛及位于其下的三个感觉神经原和三个呈同心排列的辅助细胞──鞘原细胞、毛原细胞和膜原细胞构成。几丁质表皮毛上有许多孔。毛腔内充满感受器淋巴液。感觉神经原发出的树状突伸入毛腔,浸浴于感受器淋巴液内。这些结构特征表明它是一种司嗅觉的化学感受器。雄蛾终生不取食,推断它的嗅觉感受器主要用以感受雌蛾释放的性外激素,帮助寻找配偶