Record Details
The roles of environmental constraints and aggression on male-female pairing in the coral-reef fish Gobiosoma evelynae
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The roles of environmental constraints and aggression on male-female pairing in the coral-reef fish Gobiosoma evelynae |
| Names |
Harding, Jeffrey A.
(creator) Hixon, Mark A. (advisor) |
| Date Issued | 1993-09-10 (iso8601) |
| Note | Graduation date: 1994 |
| Abstract | Early theoretical models for the evolution of male-female pairing were based largely on studies of birds. These models assumed that biparental care of eggs and young was an essential component of pairing. However, male-female pairing is also a relatively common social system in coral-reef fishes, and biparental care of young is extremely rare in this group. Although pairing has been documented in at least 13 families of reef fish, surprisingly little is known about the environmental and social factors that may maintain heterosexual pairs as the basic social units. I tested two hypotheses for pairing in a common Caribbean fish, the cleaning goby Gobiosoma evelynae, a territorial species which inhabits living coral heads. According to the Environmental Constraints Hypothesis, pairing in G. evelynae is simply a consequence of three related environmental parameters--low male mobility, low female density, and a uniform distribution of resources required by females. On reefs off St. Thomas, U.S. Virgin Islands, I found positive size-assortative pairing, frequent male movement between territories, rapid re-pairing by both males and females after experimental removal of a partner, and random distributions of apparently suitable coral heads required by females for territory space. These patterns are inconsistent with the Environmental Constraints Hypothesis for pairing. Mate Guarding is an alternative hypothesis for pairing and is based on social interactions. This hypothesis, which states that paired gobies maintain exclusive access to their partners by expelling all potential sexual rivals, predicts sex- and size-specific aggression toward conspecifics. released large and small male and female gobies directly onto the territories of pairs, and recorded the behavioral responses of the resident fish. As predicted, residents exhibited the greatest aggression toward large intruders of the same sex, and the least aggression toward large intruders of the opposite sex. Unpaired territorial females also responded aggressively to experimentally added females, and ignored added males. These results indicate that male-female pairs are maintained by mutual intrasexual aggression in this species, and that females (and possibly males) defend both partners and other resources associated with their territories. |
| Genre | Thesis/Dissertation |
| Topic | Gobiidae -- Behavior |
| Identifier | http://hdl.handle.net/1957/35775 |
