More Like this

1. Proximate determinants of family size in an obligate egg-feeding frog

   https://doi.org/10.1007/s10682-023-10255-3  

   Dugas, Matthew B.; Stevens, Trevor C.; Cosman, Madison E.; Van Dyke, Emily E.; Hernandez, Mayra D. (August 2023, Evolutionary Ecology)

   The number of offspring parents rear varies considerably among closely related lineages, individuals, and even reproductive events by one individual. Constraints can come at any point, from the costs of producing a large clutch to the cost of caring for a large brood of dependent young. We report here on observations of the early phase of a reproductive cycle in a captive colony of Oophaga pumilio, a poison frog with offspring entirely dependent on maternally provisioned trophic eggs. We tracked reproductive clutches, and found that while clutch and egg size were variable, neither predicted the success of a clutch; there was also no evidence of a trade-off between clutch and egg size. Larger eggs did, however, produce larger tadpoles, and when parents transported only a subset of the brood to nurseries, the tadpoles they moved were larger than the ones they did not. Adaptive adjustment of parental investment is a key life-history trait, and a complete accounting of the way families are constructed is key to understanding the evolution of parental care, parental favoritism, and cooperation and conflict among closely related individuals. 

   more » « less
2. Vertically transmitted microbiome protects eggs from fungal infection and egg failure

   https://doi.org/10.1186/s42523-021-00104-5  

   Bunker, M. E.; Elliott, G.; Heyer-Gray, H.; Martin, M. O.; Arnold, A. E.; Weiss, S. L. (December 2021, Animal Microbiome)

   Abstract Background Beneficial microbes can be vertically transmitted from mother to offspring in many organisms. In oviparous animals, bacterial transfer to eggs may improve egg success by inhibiting fungal attachment and infection from pathogenic microbes in the nest environment. Vertical transfer of these egg-protective bacteria may be facilitated through behavioral mechanisms such as egg-tending, but many species do not provide parental care. Thus, an important mechanism of vertical transfer may be the passage of the egg through the maternal cloaca during oviposition itself. In this study, we examined how oviposition affects eggshell microbial communities, fungal attachment, hatch success, and offspring phenotype in the striped plateau lizard, Sceloporus virgatus , a species with no post-oviposition parental care. Results Relative to dissected eggs that did not pass through the cloaca, oviposited eggs had more bacteria and fewer fungal hyphae when examined with a scanning electron microscope. Using high throughput Illumina sequencing, we also found a difference in the bacterial communities of eggshells that did and did not pass through the cloaca, and the diversity of eggshell communities tended to correlate with maternal cloacal diversity only for oviposited eggs, and not for dissected eggs, indicating that vertical transmission of microbes is occurring. Further, we found that oviposited eggs had greater hatch success and led to larger offspring than those that were dissected. Conclusions Overall, our results indicate that female S. virgatus lizards transfer beneficial microbes from their cloaca onto their eggs during oviposition, and that these microbes reduce fungal colonization and infection of eggs during incubation and increase female fitness. Cloacal transfer of egg-protective bacteria may be common among oviparous species, and may be especially advantageous to species that lack parental care. 

   more » « less
3. Lipid provisioning in eggs of an extreme dietary generalist

   https://doi.org/10.1111/phen.70019  

   Sellers, Emma J; Hicks, Kailey G; Tanino‐Springsteen, Mykaela M; Vidal, Mayra C; Murphy, Shannon M (November 2025, Physiological Entomology)

   Abstract Parents can provide care to their offspring to increase their offspring's chance of survival. There are various types of parental care across insect taxa, one of which is maternal investment. Lipids, the most energy‐dense of macronutrients, are considered a good estimate of maternal investment in insects. However, it is not clear how different environments, such as host plants, can impact provisioning, especially for dietary generalists that feed on an array of plant species with varying quality. Using an extreme dietary generalist, fall webworm (FW,Hyphantria cunea), we investigated if females provision different amounts of lipids into their eggs depending on the diet they fed upon as larvae. We measured the lipid content of FW egg clusters from parents reared on seven host plant species of varying quality. We found that parental host plants influenced egg provisioning, such that provisioning depends on host plant but also increases most for parents reared on low‐quality diets. Additionally, we found that female parents with heavier pupal mass produced egg clusters with greater lipids per egg. Our results provide evidence that egg provisioning can depend on the parental environment and suggest that the use of low‐quality host plants by generalist herbivores may be partially overcome via maternal investment. 

   more » « less
4. Urban resources limit pair coordination over offspring provisioning

   https://doi.org/10.1038/s41598-020-72951-2  

   Baldan, Davide; Ouyang, Jenny Q. (September 2020, Scientific Reports)

   Abstract The amount of care parents provide to the offspring is complicated by an evolutionary conflict of interest (‘sexual conflict’) between the two parents. Recent theoretical models suggest that pair coordination of the provisioning may reduce this conflict and increase parent and offspring fitness. Despite empirical studies showing that pair coordination is common in avian species, it remains unclear how environmental and ecological conditions might promote or limit the ability of parents to coordinate care. We compared the level of pair coordination, measured as alternation and synchrony of the nest visits, of house wrensTroglodytes aedonpairs breeding in a rural (10 nests) and a suburban (9 nests) site and investigated how differences in parental behaviours were related to habitat composition, prey abundance and how they ultimately related to reproductive success. We found that parents alternated and synchronized their nest visits more in the rural site compared to the suburban one. The suburban site is characterized by a more fragmented habitat with more coniferous trees and less caterpillar availability. Offspring from the rural site were heavier at fledging than at the suburban site. Taken together, these results suggest that environmental conditions play an important role on the emergence of coordinated parental care and that considering environmental variables is pivotal to assess the fitness consequences of parental strategies. 

   more » « less
5. Modulation of Paternal Care Behaviors in Response to Stream Conditions by Eastern Hellbenders ( Cryptobranchus alleganiensis alleganiensis )

   https://doi.org/10.1093/iob/obaf007  

   O'Brien, R_S_M; Groffen, J.; Dayer, A_A; Hopkins, W_A (February 2025, Integrative Organismal Biology)

   Synopsis The rapid environmental changes associated with the Anthropocene mean that flexible behavioral responses may be a critical determinant of animals’ resiliency to anthropogenic disturbance, particularly for species with long generation times and low vagility. One type of behavior that exemplifies this potentially important flexibility is parental care. Eggs and juvenile animals are sensitive to environmental stressors, and the ability of parents to adjust care behaviors to buffer their offspring from rapidly changing conditions may be critical to successful reproduction. In this study, we explore the role of parental care in buffering eggs from anthropogenic stressors in the long-lived, fully aquatic eastern hellbender salamander (Cryptobranchus alleganiensis alleganiensis). Using custom-designed infrared cameras installed in underwater artificial shelters in a natural stream, we describe hellbender paternal care behaviors in greater detail than has previously been possible, assess the extent to which hellbender fathers buffer their eggs from increasing levels of silt and decreasing concentrations of dissolved oxygen in nesting cavities, and describe the possible trade-offs that hellbender fathers exhibit between paternal care and self-maintenance behaviors. We found that while hellbender parents buffered their offspring from low dissolved oxygen concentrations by increasing parental care, there was an apparent trade-off between parental care and self-maintenance responses to low oxygen. Hellbender fathers did not show evidence of buffering their offspring from the effects of increasing silt or organic material in their nest cavities. We also found that filial cannibalism is a widespread behavior across nests, with almost all fathers exhibiting some cannibalism, although the extent varied widely. Our study indicates that hellbender parents may be able to reduce the impacts of declines in dissolved oxygen concentration on their offspring to a limited extent, but they may be unable to fully protect offspring from increasing silt. 

   more » « less