Seasonal dynamic shifts in patch exploitation by parasitic wasps

Roitberg, Bernard D.; Mangel, Marc; Lalonde, R. G.; Roitberg, Carol A.; Alphen, Jacques J. M. van; Vet, Louise E. M.

doi:10.1093/beheco/3.2.156

Cited by 132 publications

(92 citation statements)

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“…prolonged searching for oviposition sites, oviposition on already parasitized hosts, i.e. superparasitism) if their perceived risk of mortality increased due to changes in barometric pressure or photoperiod (Roitberg et al, 1992;Roitberg et al, 1993). Because many conditions that are favorable for reproduction vary predictably with season every year (Wingfield et al, 1992), birds can use a variety of environmental cues (e.g.…”

Section: Discussionmentioning

confidence: 99%

What comes first, the zebra finch or the egg: temperature-dependent reproductive, physiological and behavioural plasticity in egg-laying zebra finches

Salvante

Walzem

Williams

2007

Journal of Experimental Biology

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SUMMARY Avian reproduction is generally timed to synchronize chick-rearing with periods of increased food abundance. Consequently, the energetically demanding period of egg production may coincide with periods of lower food availability,fluctuating temperature and more unstable weather. Little is known about the physiological mechanisms underlying temperature-induced variation in egg production. We therefore examined the influence of low ambient temperature(7°C vs 21°C) on reproductive output (e.g. egg mass, clutch size, laying interval, laying rate), daily food consumption and lipid variables in zebra finches Taeniopygia guttata. When faced with egg production at 7°C, laying zebra finches increased energy intake by 12.67 kJ day–1, and were thus able to maintain body condition (e.g. body mass, fat and muscle score) and circulating triacylglyceride at levels comparable to those at 21°C. However, when producing eggs at 7°C,females took longer to initiate egg laying (6.5 vs 6.1 days at 21°C), and ultimately laid fewer eggs (5.5 vs 6.0 eggs) at a slower rate (0.90 eggs day–1vs 0.95 eggs day–1). These temperature-related declines in reproductive output were accompanied by decreases in modal (from 36.6 at 21°C to 24.3 nm at 7°C) and median very low density lipoprotein (VLDL) particle diameter (from 29.6 to 26.4 nm) and in the proportion of VLDL particles that were capable of passing through the pores in the ovary to access the developing ovarian follicles (i.e. particles with diameters between 25 and 44 nm; from 45.90% to 32.55%). However, variation in reproductive output was not related to any static concentration or structural measure of VLDL. Therefore,other temperature-dependent mechanisms must be involved in the physiological processes that regulate reproductive output of passerine birds at low ambient temperatures.

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Section: Discussionmentioning

confidence: 99%

What comes first, the zebra finch or the egg: temperature-dependent reproductive, physiological and behavioural plasticity in egg-laying zebra finches

Salvante

Walzem

Williams

2007

Journal of Experimental Biology

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“…Thus, our theory predicts that herbivores should always 'dump' eggs (up to the Lack clutch) as they approach the end of their life. This prediction has been upheld for parasitoids under experimental conditions (Roitberg et al, 1992. A key then is to relate eggload to future opportunities.…”

Section: Resultsmentioning

confidence: 99%

Vive la variance: a functional oviposition theory for insect herbivores

Roitberg

Robertson

Tyerman

1999

Entomologia Exp Applicata

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We developed state-dependent life-history theory to explain the variance in clutch size decisions made by insect herbivores under a variety of ecological scenarios. An important aspect of our theory is explicit representation of the distribution of host quality and frequency of occurrence. Examination of the theory suggests that clutch size decisions can be highly non-linear with respect to host quality and variability. We then use our theory to explore the potential for bet-hedging strategies to evolve as a function of unpredictable catastrophic events that decimate entire clutches. Our analysis suggests that the benefits to employing such a strategy will frequently be outweighed by costs brought on by delayed oviposition.

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“…Foraging parasitoids are known to include information gained before (Roitberg et al 1992;Visser et al 1992;Hoffmeister et al 2000), during (Driessen and Bernstein 1999 and references therein;Pierre et al 2003;van Alphen et al 2003), and between (Thiel and Hoffmeister 2004;Outreman et al 2005) patch visits in their decision-making process. However, we are far from understanding all aspects of this process.…”

Section: Discussionmentioning

confidence: 99%

The theoretical value of encounters with parasitized hosts for parasitoids

Kolß

Hoffmeister

Hemerik

2006

Behav Ecol Sociobiol

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A female parasitoid searching for hosts in a patch experiences a diminishing encounter rate with unparasitized and thus suitable hosts. To use the available time most efficiently, it constantly has to decide whether to stay in the patch and continue to search for hosts or to search for and travel to another patch in the habitat. Several informational cues can be used to optimize the searching success. Theoretically, encounters with unparasitized hosts should lead to a prolonged search in a given patch if hosts are distributed contagiously. The results of empirical studies strongly support this hypothesis. However, it has, to date, not been investigated theoretically whether encounters with already parasitized hosts (which usually entail time costs) provide a parasitoid with valuable information for the optimization of its search in depletable patches, although the empirical studies concerning this question so far have produced ambiguous results. Building on recent advances in Bayesian foraging strategies, we approached this problem by modeling a priori searching strategies (which differ in the amount of information considered) and then testing them in computer simulations. By comparing the strategies, we were able to determine whether and how encounters with already parasitized hosts can yield information that can be used to enhance a parasitoid's searching success.

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Seasonal dynamic shifts in patch exploitation by parasitic wasps

Cited by 132 publications

References 0 publications

What comes first, the zebra finch or the egg: temperature-dependent reproductive, physiological and behavioural plasticity in egg-laying zebra finches

What comes first, the zebra finch or the egg: temperature-dependent reproductive, physiological and behavioural plasticity in egg-laying zebra finches

Vive la variance: a functional oviposition theory for insect herbivores

The theoretical value of encounters with parasitized hosts for parasitoids

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