Jacques J. M. van Alphen

Learn More
Evolutionary loss of traits can result from negative selection on a specific phenotype, or if the trait is selectively neutral, because the phenotype associated with the trait has become redundant. Even essential traits may be lost, however, if the resulting phenotypic deficiencies can be compensated for by the environment or a symbiotic partner. Here we(More)
Females of the larval parasitoid of Drosophila, Asobara citri, from sub-Saharan Africa, defend patches with hosts by fighting and chasing conspecific females upon encounter. Females of the closely related, palearctic species Asobara tabida do not defend patches and often search simultaneously in the same patch. The effect of patch defence by A. citri(More)
Many organisms, including entomopathogenous fungi, predators or parasites, use aphids as ressources. Parasites of aphids are mostly endoparasitoid insects, i.e. insects which lay eggs inside the body of an other insect which will die as a result of their development. In this article, we review the consequences of the numerous pecularities of aphid biology(More)
Behavioral ecologists assume that animals use a motivational mechanism for decisions such as action selection and time allocation, allowing the maximization of their fitness. They consider both the proximate and ultimate causes of behavior in order to understand this type of decision-making in animals. Experimental psychologists and neuroeconomists also(More)
Hamrick (2002) contested the conclusion of our recent article on evolutionary constraints on digit numbers that in tetrapods limb reduction usually occurs via arrest of the initial development followed by degeneration (Galis et al 2001). Firstly, we agree with Hamrick that we unfortunately illustrated this phenomenon with the wrong figure: the digits in the(More)
Approximately three decades ago the question was first answered "whether parasitoids are able to assess the number or origin of eggs in a host" for a solitary parasitoid, Leptopilina heterotoma, by fitting theoretically derived distributions to empirical ones. We extend the set of different theoretically postulated distributions of eggs among hosts by(More)
Metabolic rate, a physiological trait closely related to fitness traits, is expected to evolve in response to two main environmental variables: (1) climate, low metabolic rates being found in dry and hot regions when comparing populations originating from different climates in a common garden experiment and (2) resource limitations, low metabolic rates(More)
Temperature increase can affect physiological and behavioural constraints. Here, we use a stochastic dynamic modelling approach to predict changes in physiological adaptations and behaviour in response to temperature increase of pro-ovigenic parasitoids (i.e., parasitoids that mature all of their eggs before emergence). Adults of most species of(More)
Medications and radiographic contrast dyes are sometimes detected in surface waters, ground water and drinking water; these have proven detrimental effects on organisms living in such waters The concentration of medications found in drinking water is at least a thousand times below their minimum therapeutic dosages. In humans, the long-term effects of daily(More)
  • 1