摘要:

Literature describing experiments and theories on factors affecting spider ballooning is deficient and what does exist is often contradictory between authors. Most work has been done on the meteorological conditions at the time of take-off. The one factor that is widely agreed upon is the upper wind speed limit of 3 m/sec. Other factors considered important by some authors include thermal production, wind speed gradients, cloud cover, and humidity. Literature on the underlying motivation and instigation of pre-ballooning behaviour (climbing to a prominent point and silk release) is very limited and largely supposition. Temperature rise, temperature drop, humidity change, air movement, vibration, light intensity, and stress have all been suggested as initiation stimuli of ballooning behaviour. Habitat instability, dispersal strategy, mating, reduction of competition, and avoidance of cannibalism have been suggested as reasons for the evolution of ballooning behaviour by certain spider species. Spiders are important polyphagous predators on arable farmland and the high mobility of ballooning species means that they are often the first to arrive in a crop newly infested with pests, and have a role in controlling the outbreak until more specific predators arrive. In order to fully exploit the pest control potential of spiders on arable farmland more work is needed to gain a better understanding of factors controlling their distribution and movement.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523016

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The nature ol the agonistic interactions between males, competing for females or space, are compared with those between females in the spiderLycosa tarentula fasciiventris. Sex differences are found in the behavioural repertoire, the duration and the outcome of the contests. Interactions between males are shorter, less intense and less variable than those between females. The duration of male agonistic interactions does not decrease as size difference increases. Prior access to the female terrarium consistently predicts the outcome of male agonistic interactions, but size difference does not. Sex differences are interpreted in relation to the optimization of the cost-benefit balance by individuals during interactions.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523017

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper we argue that even spacing of the logarithmic diameter of canine teeth in mustelids and felids as shown by DAYAN et al. (1989a, 1990) may be more likely to result from behaviourally mediated competition for space than exploitative competition for prey resources. Felids and mustelids have several characteristics in common: a high degree of carnivory, the use of canines in threat displays, solitary living including intrasexual territories and sexual dimorphism. We model the ecological and evolutionary divergence of a character that is associated with territory defence such as canine size. We show that an assumption of size-dependent territorial aggressiveness can lead both to character divergence and to sexual dimorphism.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523018

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effects of some ecological factors on the life-style of the subsocial necrophagous ball-roller scarabCanthon cyanellus cyanelluswere evaluated by experimental analysis. Survival of offspring cared for by parents was higher than survival of offspring without parental care; the latter were immediately attacked by fungi which prevents larval development. The propensity for food to be attacked during the earlier larval stages is a selective pressure which favours parental care inC. cyanellus. Early mating increased the lifetime reproductive success of females, but decreased their longevity. FemaleC. cyanellusmaintained high reproductive success even when resource availability was uncertain. Furthermore, the longevity of the females increased with an irregular supply of food. The reproductive success of females increased with food of high nutritional quality and decreased with food of low nutritional quality.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523019

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Under natural conditions hatchlings of the land snailArianta arbustorumcannibalize unhatched sibling eggs as well as eggs from neighbouring batches. Three series of choice experiments were conducted to determine whether cannibalistic hatchlings ofA. arbustorumfrom four different populations discriminate (1) between fertilized and unfertiliz,ed eggs within the same batch, (2) between eggs containing well-developed embryos and ones with less advanced embryos, and (3) between small and large fertilized eggs. Newly-hatched snails did not discriminate between fertilized and unfertilized conspecific eggs. Similarly, hatchlings cannibalized in equal proportions eggs with well-developed embryos and eggs with less advanced embryos. However, cannibalistic hatchlings ate preferentially large eggs. The results of an additional choice experiment indicated that this size preference may be due to a higher encounter probability and/or a stronger attraction by chemical cues of larger eggs, and thus is not an actual choice made by the cannibalistic hatchling. It is suggested that the higher susceptibility of large eggs to cannibalism may act as selection pressure against increasing egg size.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523020

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The multiple mating behaviour ofApis melliferaqueens is an important reproductive characteristic of this species. Estimates of the number of drones that mate with a queen can be obtained through segregation analysis of genetic markers in samples of workers from several colonies. Statistical methods have been developed that allow estimation of this parameter using segregations of worker genotypes at one locus for which the genotypes of queens are known.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523021

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Seventeen behaviour patterns used in female-female interactions were analysed for both their frequencies and temporal relationships in Apennine chamois. Withdrawing and the Approach built up, respectively, 38.4 and 21.3% of all activities. All other behaviour patterns showed much smaller frequencies (< 8%). A close relationship was found between Approach, Lipcurl, Head down, Side Display and Stare: all aggressive patterns. Butt, Chase, Hook and Rush proved to be associated, confirming their intensive bellicose quality. The communicative function of female Lipcurl has been confirmed as an aggressive ritualised behaviour, perhaps of “male mimicry”, with elements of submissive behaviour. Low-stretch, Reactive Urination and Withdrawing grouped logether as submissive patterns. Intrasexual female behavioural sequences appeared much more predictable than those of males, which is probably related to the different gregariousness patterns of the two sexes.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523022

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The epigean characidAstyanax fasciatusdeveloped a series of cave-dwelling populations in Central Mexico. The dorsal light reaction of the epigean fish was compared with that of a phylogenetically young cave population (‘Micos’ fish) and with that of the F1and F2hybrids between the epigean and a phylogenetically old cave form (‘Pachon’ fish). The experiments revealed a slight regression of the dorsal light response in the Micos fish and an almost complete regression of this behaviour in the phylogenetically old Pachon population. A genetic analysis was performed. It suggests that the dorsal light behaviour ofA. fasciatusis based on additive gene action, a minimum number of 3 to 6 genetic factors has been calculated to be involved in this system. The results are discussed with respect to the current controversy about the causes of regressive evolution. It is suggested that the observed regression of the dorsal light behaviour in the Pachon population is due to an accumulation of degenerative, selectively neutral mutations.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523023

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Adult wood mice were tested in cages for their responses to single newborn pups and mothers of newborn litters were tested for their ability to protect litters from other adults. There was no difference in infanticidal tendencies of virgin male or females, however, males housed with perforate females were less infanticidal than those with non-perforate females. Mothers of litters were unable to prevent infanticidal intruder males entering the nest but could exclude females. These data are discussed with reference to the social organization and studies on population regulation of wood mice.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523024

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523026

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor