摘要:

ABSTRACT.1Economically important bruchid beetles likeZabrotes sub‐fasciatus(Boh.) are able to reproduce both in the field before the legume crop harvest – whilst the seeds are still enclosed within pods – and on seeds in storage sites.2To take into account this reproductive feature, the influence of pods at different stages of maturity and seeds ofPhaseolus vulgaris(Lin.) together with the influence of insemination on the reproductive activity ofZabrotes subfasciatuswere examined.3Female fecundity, insemination and ovarian production were studied under laboratory conditions approximating as closely as possible to the thermal and photoperiodic regimes of the Costa Rican region from which the experimental strain originated.4The three stages of pod maturity used in experiments (fresh green, fresh yellow and dry yellow pods, all non‐dehiscent) induced copulations and significantly stimulated oogenesis. Fecundities of females in the presence of pods were low and did not differ from controls.5The influence of bean seeds on female reproductive activity was more pronounced than that of pods. Contact with seeds led to a marked increase in the number of sexual meetings, ovarian production and egg‐laying activity. Under these conditions, eggs are laid directly on the larvae's food.6Insemination alone stimulated oogenesis but did not induce egg‐laying.7Possible additive or synergistic interactions between host plant information perceived by females, the effects of egg‐laying and insemination are suggested to explain the observed results.8The adaptive value of this form of reproductive regulation by host plant seeds and pods is discussed in terms of the natural history and oviposition behaviour ofZabrotes

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1983.tb00485.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.1Natural pupation sites and corresponding pupal colour (green or brown) were determined for samples ofBattus philenor(L.) from two Californian populations.2Larvae pupate off the ground on trees, shrubs and man‐made objects.3The vertical distribution of pupation sites and relative frequencies of pupae formed on narrow twigs and broad substrates show interpopulation variability, and seem to be determined by habitat‐specific and possibly behavioural differences among populations.4The percentage of‘mismatched’pupae in green leafy environments (brown) is greater than that on wide substrates (green). Heterogeneity in samples of the latter suggest strong but sporadic predation pressure on non‐cryptic pupae in exposed areas.5Green and brown substrates generally promoted formation of cryptic green and brown pupae although rearing conditions modified pupal colour response to substrate colour and larval pupation site choice.6Warm temperatures and long days increased the production of brown pupae. Short photoperiods increased the tendency of larvae to pupate on narrow twig‐like substrates and to form green pupae.7Green pupae show less tendency to diapause than brown pupae. The difference between percentage diapause in the two colour forms increases under conditions favouring progressively more continuous

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1983.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.1An account of the life‐history with emphasis on phenology and number of instars is presented forBelgica antarcticaJacobs, the southernmost holometabolous insect.2Contrary to earlier reports,Belgicahas four instars, in common with most other chironomids. Mean head capsule lengths varied between different populations but no overlap was found between discrete size classes of successive instars.3Belgicaoverwinters in all four instars.4Relative frequency of different instars from samples taken through the season indicates that a 2‐year life‐span is the commonest pattern.5Emergence of adults is relatively synchronous.Belgicaexhibits protandry, which may be established at the time of pup

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1983.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1983.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY