Bet Hedging and the Diapause Strategies of the Cricket Allonemobius Fasciatus

Bradford, Michael J.; Roff, Derek A.

doi:10.2307/1940482

Cited by 91 publications

(99 citation statements)

References 45 publications

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“…The polymorphism would be maintained by a shifting pattern of selection in which the optimal strategy changes from year to year, or by gene flow between populations with different strategies (Hairston & Dillon, 1990;Bradford & Roff, 1993). Studies of diapause behaviour at the individual level, including the heritability of diapause, would be necessary to resolve this question (Bradford & Roff, 1993;Hopper, 1999). Given the results presented here, it seems likely that T. dubius is a component of the delayed response seen in the natural enemy community (Turchin et&., 1999).…”

Section: Complex Emergence Patterns 231mentioning

confidence: 91%

“…while others developed immediately, even within the same tree. As environmental cues indicate the approach of summer and poor conditions for reproduction (see below), slower developing larvae may be more likely to enter diapause and wait for better opportunities (Cohen, 1970;Tauber etal., 1986;Bradford & Roff, 1993). Emergence patterns appeared more similar than different across the seasons, with season mainly serving to shift the pattern through time.…”

Section: Complex Emergence Patterns 231mentioning

confidence: 97%

“…Alternatively, it may be that the pattern observed for T. dubius is a genetic polymorphism in which different genotypes either develop immediately or undergo diapause. The polymorphism would be maintained by a shifting pattern of selection in which the optimal strategy changes from year to year, or by gene flow between populations with different strategies (Hairston & Dillon, 1990;Bradford & Roff, 1993). Studies of diapause behaviour at the individual level, including the heritability of diapause, would be necessary to resolve this question (Bradford & Roff, 1993;Hopper, 1999).…”

Section: Complex Emergence Patterns 231mentioning

confidence: 99%

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Complex emergence patterns in a bark beetle predator

Reeve

2000

Agri and Forest Entomology

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1 The emergence pattern of Thanasimus dubius (F.) (Coleoptera: Cleridae), a common predator of the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Scolytidae), was studied under field conditions across different seasons. A simple statistical model was then developed to characterize the emergence data, using the truncated geometric distribution. Data are also presented on the mortality of T. dubius eggs at various temperatures and humidities in an effort to explain certain aspects of emergence behaviour. 2 Emergence of 7'. dubius from a given tree usually occurred in several discrete episodes across a two-year period, with most individuals emerging in spring or autumn. Almost no emergence occurred in July and August, which may be an adaptation to avoid high temperature mortality. Emergence patterns appeared similar across seasons, with the time of year serving mainly to shift the pattern through time. 3 Cycles in D. frontalis abundance may be the result of delayed density dependence generated by its natural enemy complex. The predator T. dubius is likely to be an important component of this delayed density dependence, because of its lengthy development time and apparent impact on D. front&s.

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Section: Complex Emergence Patterns 231mentioning

confidence: 91%

Section: Complex Emergence Patterns 231mentioning

confidence: 97%

Section: Complex Emergence Patterns 231mentioning

confidence: 99%

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Complex emergence patterns in a bark beetle predator

Reeve

2000

Agri and Forest Entomology

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“…Plasticity describes a concerted change of a given trait over a range of environmental conditions and, thus, critically depends on the availability of cues that allow forecasting of the future state of the environment (Bradford and Roff, 1993;Simons, 2011). Bet hedging, on the other hand, describes a risk-spreading strategy as an adaptation to environmental unpredictability, producing only one fixed phenotypic condition that is suboptimally adapted to any given environment but maximizing the geometric mean fitness across generations (Philippi and Seger, 1989).…”

Section: Phenotypic Plasticity Of Fruit and Seed Heteromorphismmentioning

confidence: 99%

Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum

et al. 2016

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Understanding how plants cope with changing habitats is a timely and important topic in plant research. Phenotypic plasticity describes the capability of a genotype to produce different phenotypes when exposed to different environmental conditions. In contrast, the constant production of a set of distinct phenotypes by one genotype mediates bet hedging, a strategy that reduces the temporal variance in fitness at the expense of a lowered arithmetic mean fitness. Both phenomena are thought to represent important adaptation strategies to unstable environments. However, little is known about the underlying mechanisms of these phenomena, partly due to the lack of suitable model systems. We used phylogenetic and comparative analyses of fruit and seed anatomy, biomechanics, physiology, and environmental responses to study fruit and seed heteromorphism, a typical morphological basis of a bet-hedging strategy of plants, in the annual Brassicaceae species Aethionema arabicum. Our results indicate that heteromorphism evolved twice within the Aethionemeae, including once for the monophyletic annual Aethionema clade. The dimorphism of Ae. arabicum is associated with several anatomic, biomechanical, gene expression, and physiological differences between the fruit and seed morphs. However, fruit ratios and numbers change in response to different environmental conditions. Therefore, the life-history strategy of Ae. arabicum appears to be a blend of bet hedging and plasticity. Together with the available genomic resources, our results pave the way to use this species in future studies intended to unravel the molecular control of heteromorphism and plasticity.

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“…These artificial environments are similar to the temperature and photoperiod experienced by the first (July) and subsequent (September-October) generations at the population's site of origin. Photoperiod was varied along with temperature because photoperiod has been shown to be a reliable cue for predicting seasonal changes in temperature (Bradford and Roff, 1993). Within each temperature regime, males and females were separated upon adult ecolsion to maintain virginity.…”

Section: Study System and Temperature Regimesmentioning

confidence: 99%

Seasonality influences cuticle melanization and immune defense in a cricket: support for a temperature-dependent immune investment hypothesis in insects

Fedorka

Copeland

Winterhalter

2013

Journal of Experimental Biology

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SUMMARYTo improve thermoregulation in colder environments, insects are expected to darken their cuticles with melanin via the phenoloxidase cascade, a phenomenon predicted by the thermal melanin hypothesis. However, the phenoloxidase cascade also plays a significant role in insect immunity, leading to the additional hypothesis that the thermal environment indirectly shapes immune function via direct selection on cuticle color. Support for the latter hypothesis comes from the cricket Allonemobius socius, where cuticle darkness and immune-related phenoloxidase activity increase with latitude. However, thermal environments vary seasonally as well as geographically, suggesting that seasonal plasticity in immunity may also exist. Although seasonal fluctuations in vertebrate immune function are common (because of flux in breeding or resource abundance), seasonality in invertebrate immunity has not been widely explored. We addressed this possibility by rearing crickets in simulated summer and fall environments and assayed their cuticle color and immune function. Prior to estimating immunity, crickets were placed in a common environment to minimize metabolic rate differences. Individuals reared under fall-like conditions exhibited darker cuticles, greater phenoloxidase activity and greater resistance to the bacteria Serratia marcescens. These data support the hypothesis that changes in the thermal environment modify cuticle color, which indirectly shapes immune investment through pleiotropy. This hypothesis may represent a widespread mechanism governing immunity in numerous systems, considering that most insects operate in seasonally and geographically variable thermal environments.

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Bet Hedging and the Diapause Strategies of the Cricket Allonemobius Fasciatus

Cited by 91 publications

References 45 publications

Complex emergence patterns in a bark beetle predator

Complex emergence patterns in a bark beetle predator

Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum

Seasonality influences cuticle melanization and immune defense in a cricket: support for a temperature-dependent immune investment hypothesis in insects

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