摘要:

ABSTRACTStudies were conducted in Zimbabwe of the catch ofGlossina pallidipesAusten from an electric net plus target baited with mixtures of acetone plus carbon dioxide or 1‐octen‐3‐ol (octenol) plus carbon dioxide. For acetone dispensed alone at 5–50, 000 mg h‐1, ten‐fold increments in the dose increased the catch 1.7 times. For carbon dioxide dispensed alone, dose increments from 12 to 1201 h‐1doubled the catch, but the catch was not further increased by dispensing carbon dioxide at 600–1200 1 h‐1. For mixtures of these two odours, ten‐fold increments in the dose of carbon dioxide between 12 and 12, 0001 h‐1increased the catchc. 2.5 times if acetone was also dispensed at>50 mg h‐1; changes in the dose of acetone between 50 and 50 000 mg h‐1did not affect the catch. The addition of octenol (0.05 mg h‐1) to carbon dioxide (12–12001 h‐1) doubled the catch. Ten‐fold increments in the dose of octenol between 0.05 and 5 mg h‐1did not increase the catch significantly and the catch was independent of changes in the dose of carbon dioxide between 120 and 12001 h‐1. The behavioural basis of the dose‐response curves was investigated using an incomplete ring of electric nets to assess the flight orientation of tsetse in different odours. Upwind flight was not elicited by acetone or octenol alone, or by carbon dioxide unless it was at very high doses, however, mixtures of carbon dioxide with acetone or octenol elicited upwind flight. It is suggested that the attractiveness of mixtures of acetone and carbon dioxide is a function of the region of overlap of these two odours at above threshold concentration. Acetone and octenol on their own appear to increase the

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00496.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTBehavioural and electrophysiological responses ofSchistocerca americana(Drury) (Orthoptera: Acrididae) to chemical stimulation of the tarsi were investigated. Using restrained insects, differences in leg‐waving behaviour were observed following stimulation by sucrose and nicotine hydrogen tartrate (NHT), compared to control stimulations by water. Furthermore, free‐walking insects were able to detect NHT on leaf surfaces, resulting in leg‐raising to avoid tarsal contact.SEM studies showed the presence of numerous peg chemoreceptor sensilla on the ventral surface of the tarsus. Tip recordings from such pegs showed activity from up to three chemosensitive neurones, plus a mechanoreceptor neurone. Stimulation by NaCl and KC1 elicited similar responses from two or three neurones in all sensilla tested, with increased firing rates at higher concentrations. Sucrose caused an increase in firing rate in few sensilla. In such cases several neurones were stimulated, and there was no evidence of a specific neurone sensitive to sucrose. In contrast, NHT elicited rapid firing in a single neurone, which was not sensitive to NaCl. Stimulation by NHT also inhibited the activity of the NaCl‐sensitive neurones.Possible mechanisms for chemical discrimination inS. americanatarsi are compared with those previously proposed for grasshopper mouthpart sensilla, and the significance of a NHT‐sensitive neurone in tarsal sensilla is

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00497.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTWe determined whether female deer ticksIxodes damminiSpielman, Clifford, Piesman&Corwin (Acari: Ixodidae) can be inseminated repeatedly and whether sperm from first or second matings take precedence in fertilizing eggs. Such information is essential to the design of attempts to reduce the fertility of these vectors of Lyme disease. Although spermatophores are present in about half of questing female ticks, they are present in virtually all those found on deer; the abundance of males on deer exceeds that of females and copulation is common. Females must be inseminated before commencing the rapid engorgement phase of feeding. Males need not be in attendance during feeding, provided that the female has been inseminated preprandially. Thus, preprandial insemination suffices to stimulate rapid engorgement, but less blood is taken than when the female is perprandially inseminated. Both types of insemination effectively fertilize eggs. Eggs from females sequentially inseminated by irradiated and non irradiated males, were fertilized mainly by sperm from the last male. Cobalt‐irradiated males mate effectively and their sperm compete with those of non‐irradiated males. Sperm from the second two sequential inseminations fertilize most of the eggs. By infesting deer with such irradiated maleI.dammini, the abundance of these vector ticks may effectively be redu

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00498.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY