Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)

Reigada, Carolina; Godoy, Wesley Augusto Conde

doi:10.1590/s0102-09352006000400018

Cited by 12 publications

(9 citation statements)

References 13 publications

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“…We inferred that conspeciÞc larvae did not greatly inßuence the oviposition preference of C. megacephala. Although competition might be a very important factor affecting blow ßy Þtness, when the larval density was higher, a negative correlation was shown between density and survivorship, but when the density was lower, the dependence between density and survivorship was not signiÞcant (Reigada andGodoy 2006, Shiao andYeh 2008). In this test, the conspeciÞc larval density might not have reached the competitive stress threshold that would inßuence the oviposition preference of C. megacephala.…”

Section: Influence Of Intra-and Interspecific Interactionsmentioning

confidence: 77%

Oviposition Preferences of Two Forensically Important Blow Fly Species, Chrysomya megacephala and C. rufifacies (Diptera: Calliphoridae), and Implications for Postmortem Interval Estimation

Yang

Shiao

2012

jnl. med. entom.

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Necrophagous blow fly species (Diptera: Calliphoridae) are the most important agents for estimating the postmortem interval (PMI) in forensic entomology. Nevertheless, the oviposition preferences of blow flies may cause a bias of PMI estimations because of a delay or acceleration of egg laying. Chrysomya megacephala (F.) and C. rufifacies (Macquart) are two predominant necrophagous blow fly species in Taiwan. Their larvae undergo rather intense competition, and the latter one can prey on the former under natural conditions. To understand the oviposition preferences of these two species, a dual-choice device was used to test the choice of oviposition sites by females. Results showed when pork liver with and without larvae of C. rufifacies was provided, C. megacephala preferred to lay eggs on the liver without larvae. However, C. megacephala showed no preference when pork liver with and without conspecific larvae or larvae of Hemipyrellia ligurriens (Wiedemann) was provided. These results indicate that females of C. megacephala try to avoid laying eggs around larvae of facultatively predaceous species of C. rufifacies. However, C. rufifacies showed significant oviposition preference for pork liver with larvae of C. megacephala or conspecific ones when compared with pork liver with no larvae. These results probably imply that conspecific larvae or larvae of C. megacephala may potentially be alternative food resources for C. rufifacies, so that its females prefer to lay eggs in their presence. When considering the size of the oviposition media, pork livers of a relatively small size were obviously unfavorable to both species. This may be because females need to find sufficient resources to meet the food demands of their larvae. In another experiment, neither blow fly species showed an oviposition preference for pork livers of different stages of decay. In addition, the oviposition preferences of both species to those media with larvae were greatly disturbed in a dark environment. If we removed the larvae that had previously fed on the pork liver and let the females choose, no oviposition preference was observed; but both species still showed a preference for the larger media in the dark. This suggests that female blow flies can use visual cues to recognize larvae on the media and decide on their oviposition site. Our studies point out the effects of some biotic and abiotic factors which were previously overlooked, and remind us to reevaluate these effects on oviposition, especially when using insect developmental data to estimate PMIs.

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Section: Influence Of Intra-and Interspecific Interactionsmentioning

confidence: 77%

Oviposition Preferences of Two Forensically Important Blow Fly Species, Chrysomya megacephala and C. rufifacies (Diptera: Calliphoridae), and Implications for Postmortem Interval Estimation

Yang

Shiao

2012

jnl. med. entom.

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“…Reigada and Godoy () studied the effects of larval density on the dynamics of the fly Chrysomya megacephala at two temperatures in a laboratory environment and found that fecundity declines with increasing density and temperature, which may lead to a transition from a two‐point limit cycle to a stable equilibrium. While plant bug fecundity also declines with increasing density, fecundity exhibits a unimodal temperature response.…”

Section: Discussionmentioning

confidence: 99%

“…Our model also predicts that mortality increases with increasing temperatures; however, temperature effects on population density are more complex as the underlying life-history and competitive traits are also temperature-dependent. Reigada and Godoy (2006) studied the effects of larval density on the dynamics of the fly Chrysomya megacephala at two temperatures in a laboratory environment and found that fecundity declines with increasing density and temperature, which may lead to a transition from a twopoint limit cycle to a stable equilibrium. While plant bug fecundity also declines with increasing density, fecundity exhibits a unimodal temperature response.…”

Section: Discussionmentioning

confidence: 99%

Effects of temperature and resource variation on insect population dynamics: the bordered plant bug as a case study

et al. 2015

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Summary In species with complex life cycles, population dynamics result from a combination of intrinsic cycles arising from delays in the operation of negative density-dependent processes (e.g., intraspecific competition) and extrinsic fluctuations arising from seasonal variation in the abiotic environment. Abiotic variation can affect species directly through their life history traits and indirectly by modulating the species’ interactions with resources or natural enemies.We investigate how the interplay between density-dependent dynamics and abiotic variability affects population dynamics of the bordered plant bug (Largus californicus), a Hemipteran herbivore inhabiting the California coastal sage scrub community. Field data show a striking pattern in abundance: adults are extremely abundant or nearly absent during certain periods of the year, leading us to predict that seasonal forcing plays a role in driving observed dynamics.We develop a stage-structured population model with variable developmental delays, in which fecundity is affected by both intra-specific competition and temporal variation in resource availability and all life history traits (reproduction, development, mortality) are temperature-dependent. We parameterize the model with experimental data on temperature-responses of life history and competitive traits and validate the model with independent field census data.We find that intra-specific competition is strongest at temperatures optimal for reproduction, which theory predicts leads to more complex population dynamics. Our model predicts that while temperature or resource variability interact with development-induced delays in self-limitation to generate population fluctuations, it is the interplay between all three factors that drive the observed dynamics. Considering how multiple abiotic factors interact with density-dependent processes is important both for understanding how species persist in variable environments and predicting species’ responses to perturbations in their typical environment.

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“…This is because intraspecific competition is the major mechanism of negative densitydependent feedback underlying population regulation, a critical prerequisite for species coexistence. Empirical studies show that the effects of intraspecific competition on life-history traits is strongly temperature dependent (Ritchie 1996; Reigada and Godoy 2006;Laws and Belovsky 2010). However, theoretical work on temperature effects on species interactions has considered intraspecific competition to be temperature independent.…”

Section: Introductionmentioning

confidence: 99%

Effects of Temperature on Intraspecific Competition in Ectotherms

Amarasekare

Coutinho

2014

The American Naturalist

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Understanding how temperature influences population regulation through its effects on intraspecific competition is an important question for which there is currently little theory or data. Here we develop a theoretical framework for elucidating temperature effects on competition that integrates mechanistic descriptions of life-history trait responses to temperature with population models that realistically capture the variable developmental delays that characterize ectotherm life cycles. This framework yields testable comparative predictions about how intraspecific competition affects reproduction, development, and mortality under alternative hypotheses about the temperature dependence of competition. The key finding is that ectotherm population regulation in seasonal environments depends crucially on the mechanisms by which temperature affects competition. When competition is strongest at temperatures optimal for reproduction, effects of temperature and competition act antagonistically, leading to more complex dynamics than when competition is temperature independent. When the strength of competition increases with temperature past the optimal temperature for reproduction, effects of temperature and competition act synergistically, leading to dynamics qualitatively similar to those when competition is temperature independent. Paradoxically, antagonistic effects yield a higher population floor despite greater fluctuations. These findings have important implications for predicting effects of climate warming on population regulation. Synergistic effects of temperature and competition can predispose populations to stochastic extinction by lowering minimum population sizes, while antagonistic effects can increase the potential for population outbreaks through greater fluctuations in abundance.

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Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)

Cited by 12 publications

References 13 publications

Oviposition Preferences of Two Forensically Important Blow Fly Species, Chrysomya megacephala and C. rufifacies (Diptera: Calliphoridae), and Implications for Postmortem Interval Estimation

Oviposition Preferences of Two Forensically Important Blow Fly Species, Chrysomya megacephala and C. rufifacies (Diptera: Calliphoridae), and Implications for Postmortem Interval Estimation

Effects of temperature and resource variation on insect population dynamics: the bordered plant bug as a case study

Effects of Temperature on Intraspecific Competition in Ectotherms

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