Dissertation
Ethology and neurobiology of xeric-adapted isopods: plasticity in bi-parental care and neuroanatomy of Hemilepistus reaumuri (Milne-Edwards, 1840) (Isopoda: Agnaridae)
Doctor of Philosophy (Ph.D.), Drexel University
Mar 2025
DOI:
https://doi.org/10.17918/00010894
Abstract
Families are the basic units of most animal societies, yet collaborative parental care is rare. Brain structure can change to accommodate the cognitive requirements of new behaviors such as the onset of parental care in fish, rodents, and primates. I asked whether similar patterns in neural and behavioral plasticity hold in arthropods. Hemilepistus reaumuri is a terrestrial isopod that exhibits bi-parental care by guarding the burrow and providing food for its offspring, making it an ideal model for investigating brain plasticity. To describe the neuroanatomical structure of H. reaumuri, I used traditional histology, immunohistochemistry, and nanoCT imaging. I focused on the localization of the antibody "anti-DC0", which is the diagnostic tool for describing insect and crustacean mushroom bodies because it is known to target and visualize regions that support learning and memory. I also described the structure of the central complex which supports parental behaviors such as foraging through the integration of first order sensory inputs into navigation and motor control. To characterize brain plasticity associated with the onset of parental care, I sampled isopods throughout development and found that their central body increased in volume relative to body size from immature to adult phases, associated with changes in body size. There was further body-size independent expansion of the central body in fully grown adults, associated with the transitions between young adult, gestation, and parental provisioning. To compare the behavior of bi-parental isopods to a missing partner, I conducted a field manipulation in which pairs of isopod parents were either left and observed as pairs or manipulated by the removal of one partner. The number of foraging trips decreased at a faster rate for unpaired males than for paired males; this pattern was not seen in females. Females started and ended foraging at the same time regardless of the manipulation and throughout the entire experiment, while unpaired males started foraging later in the day over time, and paired males started earlier. These results indicated some flexibility, mostly on the part of males, to adjust their behavior in response to the loss of a partner. In a final chapter, I provide a published natural history note describing the tendency of other xeric-adapted isopods to follow ant trails and spend time inside their nests.
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Details
- Title
- Ethology and neurobiology of xeric-adapted isopods
- Creators
- Karmi Leah Oxman
- Contributors
- Sean O'Donnell (Advisor)Jacob A. Russell (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xii, 130 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Biodiversity, Earth, and Environmental Science (BEES); College of Arts and Sciences; Drexel University
- Other Identifier
- 991022040862704721