Ian C. W. Hardy

Learn More
The existence of spiteful behaviors remains controversial. Spiteful behaviors are those that are harmful to both the actor and the recipient, and they represent one of the four fundamental types of social behavior (alongside selfishness, altruism, and mutual benefit). It has generally been assumed that the conditions required for spite to evolve are too(More)
2000: Insemination capacity and dispersal in relation to sex allocation decisions in Goniozus legneri (Hymenoptera: Bethylidae): why are there more males in larger broods? Ethology 106, 1021Ð1032. Abstract Models considering sex ratio optima under single foundress strict local mate competition predict that female bias will be reduced by stochasticity in sex(More)
Kin selection theory predicts that individuals will show less aggression and more altruism towards relatives. However, recent theoretical developments suggest that with limited dispersal, competition between relatives can override the effects of relatedness. The predicted and opposing influences of relatedness and competition are difficult to approach(More)
Owners have often been found to have an advantage in animal contests. One explanation of this is that the resource under dispute is of greater value to the owner than to the intruder (nonowner). Such 'resource value asymmetries' may be caused by intrinsic factors, such as the physiological state of the contestants. Females of the bethylid wasp Goniozus(More)
Copidosoma sp. is a polyembryonic encyrtid wasp which parasitizes isolated hosts. Most broods of this wasp are unisexual, but some contain both sexes and the secondary sex ratio of these is usually highly female biased. The overall population secondary sex ratio is female biased. Walter and Clarke (1992) argue that because the majority of individuals must(More)
Many agricultural pests can be harboured by alternative host plants but these can also harbour the pests’ natural enemies. We evaluated the capacity of non-cotton plant species (both naturally growing and cultivated) to function as alternative hosts for the cotton leaf hopper Amrasca devastans (Homoptera: Ciccadellidae) and its natural enemies. Forty-eight(More)
Population-wide mating patterns can select for equal parental investment in both sexes, but limiting resources, such as mates or developmental substrates, can increase competition leading to biased sex ratios in favor of either sex. Such competition for resources typically occurs in spatially structured populations, where dispersal is limited. In this(More)
Two major categories of factors are predicted to influence behaviour in dyadic contests; differences in the abilities of the contestants to acquire and retain resources (resource holding potential), and the value of the contested resource (resource value, RV; which comprises objective and subjective components). Recent studies indicate that subjective(More)
Selfish interests usually preclude resource sharing, but under some conditions collective actions enhance per capita gains. Such Allee effects underlay early explanations of social evolution but current understanding focusses on kin selection (inclusive fitness). We find an Allee effect that explains unusual quasisociality (cooperative brood care) among(More)