Abstract Fitness, defined as the per capita rate of increase a genotype with reference to population carrying associated genes, is concept used by biologists describe how well an individual performs in population. Fitness rarely measured directly and resort proxies more easily but varying connection fitness. Size, progeny survival, developmental are most common literature parasitoid The importance varies between papers looking at evolutionary theories those assessing ecological applications....

Most experiments on thinning effects are based upon short-term outcomes, which has led to a common conclusion that stand gross volume will be reduced after various operations. However, contrary results emerging from more recent long-term experiments. The well-known biological concept of compensatory growth was introduced reconcile these opposing results. This synthetic article describes systematic investigation overcompensation under the conceptual framework and consists following: (1)...

We developed and tested predictions of a dynamic life history model that is concerned with how temperate-zone parasitic wasps adjust patch residence time tendency to superparasitize when expectation habitat quality varies. The theory predicts short expectancy should continue search longer more frequently than similar long expectancy. Similarly, forage in habitats where patches are already heavily exploited foraging relatively unexploited. In contrast, the will be insensitive quality. on...

Journal Article Insects that Mark Host Plants Get access Bernard D. Roitberg, Roitberg Search for other works by this author on: Oxford Academic Google Scholar Ronald J. Prokopy BioScience, Volume 37, Issue 6, June 1987, Pages 400–406, https://doi.org/10.2307/1310563 Published: 01 1987

SUMMARY (1) This paper examines the influence of predators on dispersal apterous pea aphids in laboratory and field. (2) Individual can be placed one two categories, searchers runners, depending upon behaviour they exhibit after dropping from their host plant. (3) In field cages, readily disperse to new plants presence predators. Dispersal is rare when active are absent. (4) Evidence presented which suggests fecundity reduced day an aphid disperses. (5) The distance dispersed by nymphs...

(4) Flies never or rarely oviposited in non-host and marked fruit respectively, both cases emigrated from trees harbouring those soon after examining the fruit. (5) exhibited success-motivated search following discovery of oviposition uninfested, unmarked (6) visited more fruit, often remained longer high v. low densities clusters. (7) sooner last egg they laid on high, low, clusters (Giving Up Time shorter). (8) Rhagoletis pomonella foraging behaviour is discussed relation to current theory.

Abstract. 1. Female apple maggot (Rhagoletis pomonella Walsh) flies held in field cages usually oviposited an unparasitized (non‐pheromone marked) fruit when it was encountered. 2. Oviposition a previously parasitized (pheromone depended upon the time since last oviposition (TSLO) and percentage of infested encountered during search for sites. 3. Previous theories host acceptance suggest that or rejection should depend dichotomously on fraction marked hosts five encounters. The experiments,...

Heat waves – extended periods of abnormally hot weather are predicted to increase in severity and frequency under climate change. The heat should impact communities food webs through effects on performance individual species changes the strength interactions between them. This study tested simulated waves, with daily maxima either 32°C or 40°C, a tritrophic web consisting plants, Capsicum anuum , aphids, Myzus persicae two parasitoids, Aphidius matricariae Aphelinus abdominalis . Osmolarity...

Trophic egg‐laying – wherein mothers provide non‐developing eggs for offspring to eat has attracted much empirical attention diverse taxa (e.g. amphibians, non‐social and eusocial insects, fish, marine gastropods). However, there been only a limited exchange of ideas among studies different taxa. We advocate unified approach the study trophic within an evolutionary ecological framework. In this paper, we stress importance elucidating adaptive function through explicit hypothesis testing, our...

Adult and fourth-instar pea aphids from Vancouver, B.C., responded to alarm pheromone by either dropping, running, or backing up. Younger instars showed almost no response but all a pheromone–vibratory stimulus, usually dropping. We suggest that younger respond conservatively because they are less agile on the ground more likely die there before finding suitable food plant. hot, dry region of British Columbia do not This is due high risk associated with any instar leaving host plant where...

ABSTRACT. The response of host‐depibved Rhagoletis pomonella Walsh (Diptera, Tephritidae) females to host fruit ( Crataegus viridis L.) marked with R.pomonella oviposition deterring pheromone was measured in the laboratory. A positive correlation found between length deprivation (5, 10, 20, 40 or 80 min) and probability acceptance (i.e. oviposition) by flies. results are discussed relation current theories on physiological control insect feeding behaviour.

The diversity of parasitic insects remains one the most conspicuous patterns on planet. principal factor thought to contribute differentiation populations and ultimately speciation is intimate relationship parasites share with hosts potential for disruptive selection associated using different host species. Traits that generate this have been an intensely debated topic central importance evolution specialization maintenance ecological diversity. A fundamental hypothesis surrounding no single...

Abstract Pea aphids can avoid ladybug predators by dropping from the food plant when disturbed. Once off aphid must find another plant. If temperatures on ground are high, may die before finding a new In Kamloops, B.C., summers hot and dry, compared with Vancouver where climate is warm moist. Kamloops generally exhibit back-up behaviour rarely drop approached ladybug. By contrast, pea readily disturbed predator. Adult more tolerant of heat under moist conditions at 37.5 °C than adults but...

Abstract The reproductive success of female parasitoids is dependent on their ability to accurately assess the suitability a host for larval development. For generalist parasitoids, which utilize broad range species and instars as hosts, set assessment criteria determines whether accepted or rejected. host, however, can only be imperfectly assessed by parasitoid, result in selection lesser quality hosts oviposition. In this study we explored disparity between preference using koinobiotic...

Journal Article Searching Behavior: the Behavioral Ecology of Finding Resources Get access The ResourcesBell William J. Chapman and Hall, New York, 1991 345 pp., $69.95 ISBN 0-412-29210-6 Bernard D. Roitberg Department Biological Sciences Simon Fraser Univ. Burnaby, British Columbia. Search for other works by this author on: Oxford Academic Google Scholar Annals Entomological Society America, Volume 85, Issue 1, 1 January 1992, Pages 108–109, https://doi.org/10.1093/aesa/85.1.108 Published: 01 1992