Contest and scramble competition in two bruchid species, <i>Callosobruchus analis</i> and <i>C. phaseoli</i> (Coleoptera: Bruchidae) I. Larval competition curves and interference mechanisms

Toquenaga, Yukihiko; Fujii, Koichi

doi:10.1007/bf02512569

Cited by 43 publications

(47 citation statements)

References 24 publications

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“…2). The competition curves of the beetle showed a humped shape which is typically observed in scramble competition (Toquenaga and Fujii, 1990;Mano et al, 2002) (Fig. 2) and the reduction of size was likely due to sharing the food resources between larvae (Nicholson, 1954).…”

Section: Discussionmentioning

confidence: 74%

Effects of larval density on larval survivorship and imaginal fecundity of Dacnepicta (Coleoptera: Erotylidae)

Sato

Shinkaji

Amano

2004

Appl. Entomol. Zool.

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Adults of Dacne picta (Coleoptera: Erotylidae) show heavy aggregation in the field and they also vary considerably in size. To investigate the factors influencing the size and the effect of larval density on post-embryonic development and adult size, we conducted a laboratory experiment in which we varied the food quantity available to each larvae. The stage of larvae most critical for intraspecific competition was also estimated by the food consumption and adult size. Experimental manipulation of larval density revealed that adult size is affected by larval density, and adults of various sizes emerged from the high density plot. Larval density had no effect on pupation, though there was severe intraspecific competition at high densities. Thus, the typical competition among larvae was considered to be of the scramble type, but it changed to contest at extremely high larval densities. For female adults, lifetime and lifetime fecundity were reduced with decreased size. These results suggest that the beetles show a mainly scramble competition of larvae, but emerged adults inevitably suffer reduction in reproductive traits.

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Section: Discussionmentioning

confidence: 74%

Effects of larval density on larval survivorship and imaginal fecundity of Dacnepicta (Coleoptera: Erotylidae)

Sato

Shinkaji

Amano

2004

Appl. Entomol. Zool.

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“…Adult lifespan ranges between 6 and 10 days (Maklakov et al 2007a) and the development time between 19 and 25 days under these conditions. Because female C. maculatus produce approximately 100 eggs during their lifetime under our experimental conditions, which are evenly distributed among available beans, and because each bean can harbour several (four to five) larvae without reduced survival, this design minimizes the effects of differential larval survival owing to juvenile competition within beans (Toquenaga & Fujii 1990). We derived three alternative measures of population fitness, representing both rate-insensitive and rate-sensitive metrics (Heesterbeek 2002;Brommer et al 2004;Roff 2008).…”

Section: Methodsmentioning

confidence: 99%

Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles

Arnqvist

Tuda

2009

Proc. R. Soc. B.

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Although males and females share much of the same genome, selection is often distinct in the two sexes. Sexually antagonistic loci will in theory cause a gender load in populations, because sex-specific selection on a given trait in one sex will compromise the adaptive evolution of the same trait in the other sex. However, it is currently not clear whether such intralocus sexual conflict (ISC) represents a transient evolutionary state, where conflict is rapidly resolved by the evolution of sexual dimorphism (SD), or whether it is a more chronic impediment to adaptation. All else being equal, ISC should manifest itself as correlated evolution between population fitness and SD in traits expressed in both sexes. However, comparative tests of this prediction are problematic and have been unfeasible. Here, we assess the effects of ISC by comparing fitness and SD across distinct laboratory populations of seed beetles that should be well adapted to a shared environment. We show that SD in juvenile development time, a key life-history trait with a history of sexually antagonistic selection in this model system, is positively related to fitness. This effect is due to a correlated evolution between population fitness and development time that is positive in females but negative in males. Loosening the genetic bind between the sexes has evidently allowed the sexes to approach their distinct adaptive peaks.

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“…When larvae of different species meet in a bean, a C. maculatus larva is likely to bite and kill a C. chinensis larva, but the opposite direction does not (i.e. interference competition; Umeya et al 1975, Toquenaga and Fujii 1990, Kishi et al 2009). Then C. maculatus is stronger in RC.…”

Section: Introductionmentioning

confidence: 99%

Identifying critical interactions in complex competition dynamics between bean beetles

Kawatsu

Kishi

2017

Oikos

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Identifying behavioural basis of competitive relationship is essential to understand outcome of interspecific competition. However, it remains difficult to investigate demographic effect of competitive behaviour, because various kinds of behaviours may co-occur in the competition and make the dynamics far complicated in nonlinear ways. We report that the behavioural basis of interspecific interaction can be identified, by focusing on the timescale difference from the occurrence of each behaviour to the appearance of its demographic effect. Between two bean beetles, Callosobruchus chinensis and C. maculatus, major interspecific interactions are resource competition (RC) at the larval stage and reproductive interference (RI) at the adult stage. RC has longer time lag than RI, because effect of RC appears in the adult number of the next generation through larval competition while effect of RI appears instantaneously in the adult number through early death of females. If we detect two effects with different time lags from the competition dynamics, an effect with intergenerational time lag and with no time lag would be considered as RC and RI, respectively. We applied empirical dynamic modelling approach, which is a nonlinear time series analysis for detecting causal interactions and the strength, to two published datasets of experimental competition between those beetles. Results showed the significant causality from the winner species to the loser one in both experiments, but the causality time lag differed between experiments: the causality had no time lag in the C. chinensis-win data, while intergenerational time lag in C. maculatus-win data. Furthermore, detection of the causality with intergenerational time lag from C. maculatus to C. chinensis in both experiments suggests interplay of constant RC and variable RI which can reverse the outcome. This study is the first successful case study that links behavioural-level interactions to demographic-level effects in interspecific competition.

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Contest and scramble competition in two bruchid species, Callosobruchus analis and C. phaseoli (Coleoptera: Bruchidae) I. Larval competition curves and interference mechanisms

Cited by 43 publications

References 24 publications

Effects of larval density on larval survivorship and imaginal fecundity of Dacnepicta (Coleoptera: Erotylidae)

Effects of larval density on larval survivorship and imaginal fecundity of Dacnepicta (Coleoptera: Erotylidae)

Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles

Identifying critical interactions in complex competition dynamics between bean beetles

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