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By influencing offspring development and survival, parental effects have the potential to aid responses to rapid environmental change. We examined whether Onthophagus taurus dung beetles modified breeding behaviors in response to climate change conditions, and as a result, buffered their offspring from increasing temperatures during development. We conducted a breeding experiment under miniature greenhouses in the field and tracked female reproductive behaviors and offspring phenotype and survival. Dung beetles lay eggs inside of brood balls made of dung and bury them underground. Burial depth influences the temperatures offspring experience during development – with deeper depths offering cooler, less variable temperatures – which can have profound effects on development. We put females in ambient or greenhouse treatments and measured brood ball production, mass, and burial depth.We allowed offspring to develop underground at the maternal burial depth until eclosion, and measured offspring survival, mass, and sex. Females in the greenhouse treatment buried brood balls deeper than those in the ambient treatment, such that offspring developed at similar temperatures in both treatments. As a result, offspring survival was similar between treatments, but body size was smaller, and more females were produced in the greenhouse treatment. Our results demonstrate that parental effects can buffer offspring survival from climate change, underscoring the importance of plasticity in climate change responses.
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The impacts of climate change on secondary seed dispersal in dung beetles
Dung beetles, which move and bury the feces of vertebrates, are major drivers of ecosystem processes and provide crucial ecosystem services, including secondary seed dispersal. Dung beetles bury seed-containing dung in food caches or in brood balls used for breeding purposes, but little is known about how this behavior will be affected by climate change. We utilized field manipulations to investigate the effect of simulated climate change—including simultaneous increases in temperature mean and variance—on the seed dispersal behavior of two tunneling dung beetle species, Phanaeus vindex and Onthophagus taurus. We placed single adult females into either control or greenhouse treatments along with temperature loggers. We mixed glass beads of three sizes into cow dung to mimic seeds, provided beetles with the dung, and then allowed them to bury dung for either six or nine days. At the end of each trial, we recorded information on dung deposits, including the type (i.e., food cache or brood ball), number, size, burial depth, and the amount of each bead size found in the deposit. We found differences in burial depths of brood balls and food caches within species, as well as differences in the size and amount of beads buried between species. Exposure to higher temperatures resulted in brood balls being buried deeper across species, but did not change the burial depth of food caches.
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- Award ID(s):
- 2046368
- PAR ID:
- 10542375
- Publisher / Repository:
- Integrative and Comparative Biology
- Date Published:
- Volume:
- 64
- Issue:
- Supplement_1
- Page Range / eLocation ID:
- S1–S581
- Format(s):
- Medium: X
- Location:
- https://doi.org/10.1093/icb/icae140
- Sponsoring Org:
- National Science Foundation
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Temperature profoundly impacts insect development, but plasticity of reproductive behaviours may mediate the impacts of temperature change on earlier life stages. Few studies have examined the potential for adult behavioural plasticity to buffer offspring from the warmer, more variable temperatures associated with climate change. We used a field manipulation to examine whether the dung beetle Phanaeus vindex alters breeding behaviours in response to temperature changes and whether behavioural shifts protect offspring from temperature changes. Dung beetles lay eggs inside brood balls made of dung that are buried underground. Brood ball depth impacts the temperatures offspring experience with consequences for development. We placed adult females in either control or greenhouse treatments that simultaneously increased temperature mean and variance. We found that females in greenhouse treatments produced more brood balls that were smaller and buried deeper than controls, suggesting brood ball number or burial depth may come at a cost to brood ball size, which can impact offspring nutrition. Despite being buried deeper, brood balls from the greenhouse treatment experienced warmer mean temperatures but similar amplitudes of temperature fluctuation relative to controls. Our findings suggest adult behaviours may partially buffer developing offspring from temperature changes.more » « less
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Temperature strongly affects insect development, but plasticity of adult reproductive behaviors can alter the temperatures experienced by earlier life stages. To date, few studies have tested whether adult behavioral plasticity can protect offspring from the warmer,more variable temperatures linked to climate change. Here I discuss laboratory experiments and field manipulations in which my lab has examined whether the adults of three dung beetle species modify their breeding behaviors in response to increases in temperature mean and variance and whether these behavioral shifts can protect dung beetle offspring from temperature changes. Tunnelling dung beetles lay their eggs inside brood balls constructed of dung that are buried below the soil surface. The depth of the brood ball affects the temperatures that the offspring experience and, thus, offspring development. Based on lab and field studies, all three species placed brood balls deeper in the soil in response to warmer and more variable temperatures, but for some species, the greater burial depth came at a cost to brood ball size and/or number, which can impact fitness. Despite greater burial depths, offspring in brood balls in the heated treatments still experienced warmer mean temperatures, which had a large, negative effect on offspring survival of the species with the smallest body size. These findings suggest adult behaviors could partially shield developing offspring from temperature changes.more » « less
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