Abstract
Under the hypothesis of environmentally cued hatching (ECH), eggs are stimulated to hatch by cues favouring larval survival. Here we investigated whether the bird-parasitic nest fly Philornis downsi Dodge & Aitken (Diptera: Muscidae) exhibits ECH in response to the presence of suitable hosts and environmental conditions. Philornis downsi is an invasive in the Galapagos Islands and ECH could help to explain its success in a novel habitat. We found that the presence of hosts (nesting birds) per se does not accelerate hatching time in P. downsi, but that nesting birds do produce a microclimate, in terms of temperature and/or humidity that is conducive to faster hatching and higher hatching success. Eggs that are laid under extremely dry conditions die rather than delay their hatching time. We also found that P. downsi eggs hatch more rapidly when the substrate is very wet. Furthermore, larvae that hatch rapidly survive longer under starvation conditions. We suggest that eggs hatching more rapidly can either take advantage of optimal conditions for larval growth (host presence) or escape unfavourable microclimatic conditions (as larvae are mobile).
| Original language | English (US) |
|---|---|
| Pages (from-to) | 752-760 |
| Number of pages | 9 |
| Journal | Entomologia Experimentalis et Applicata |
| Volume | 166 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 2018 |
Bibliographical note
Funding Information:We thank Alain Caron, François Grégoire, and Ian Lane for their help in statistical analyses; Ismael Ramirez and Johanna Castañeda for supplying us with flies; Nik Prenevost, Stephanie Dahl, Mariana Bulgarella, Jonathan Dregni, Carleigh Windhorst, Ashley Sampedro, and Justine Bleick for help in the quarantine facility; and Sarah Knutie and two anonymous reviewers for helpful comments on the manuscript. This work was supported in part by funding from the International Community Foundation (with a grant awarded by The Leona M. and Harry B. Helmsley Charitable Trust), Galapagos Conservancy, and awards from the National Geographic Society and the University of Minnesota Institute on the Environment. This is contribution number 2198 of the Charles Darwin Foundation for the Galápagos Islands.
Funding Information:
We thank Alain Caron, Fran©cois Grégoire, and Ian Lane for their help in statistical analyses; Ismael Ramirez and Johanna Castañeda for supplying us with flies; Nik Prene-vost, Stephanie Dahl, Mariana Bulgarella, Jonathan Dregni, Carleigh Windhorst, Ashley Sampedro, and Jus-tine Bleick for help in the quarantine facility; and Sarah Knutie and two anonymous reviewers for helpful comments on the manuscript. This work was supported in part by funding from the International Community Foundation (with a grant awarded by The Leona M. and Harry B. Helmsley Charitable Trust), Galapagos Conservancy, and awards from the National Geographic Society and the University of Minnesota Institute on the Environment. This is contribution number 2198 of the Charles Darwin Foundation for the Galápagos Islands.
Publisher Copyright:
© 2018 The Netherlands Entomological Society
Keywords
- Darwin's finches
- Diptera
- ECH
- Estrildidae
- Galapagos
- Muscidae
- chorion
- humidity
- insect egg
- invasion
- oviposition
- plasticity
- society finch