More is not better: Costs of pleometrosis in the neotropical termite Nasutitermes corniger

Most termite species found colonies in monogamous pairs, while Nasutitermes corniger may establish new colonies either as queen-king pairs or multiple founder associations (MFAs) of more than one king and/or queen. To understand the potential benefits of pleometrosis, we examined the reproductive output and behavior of pairs, trios, and quintets during the initial stages of colony foundation. We hypothesized that MFAs would lay more eggs/colony and provide a higher level of parental care, resulting in faster colony growth rates to attain a critical mass sooner than smaller groups. Observations of over 150 hours of video, however, indicated that while larger groups had higher overall activity levels, most behaviors were directed toward the other reproductives rather than toward offspring. Individuals in trios and quintets spent more time and interacted more frequently with one another than did individuals in pairs. Pairs laid eggs and hatched larvae more frequently than trios and quintets. Pairs that oviposited exhibited more parental behaviors than fecund MFAs. These results suggest that MFAs may not result in more parental care or increased colony growth. Instead, they may actually carry a fitness cost. Increased levels inter-adult interactions amongst members of MFAs may indicate high levels of vigilance, competition, and agonism, ultimately decreasing reproductive output. Pairs, with lower levels of inter-adult interactions, have more time and energy for oviposition and better care for offspring.