The female perspective on reproductive strategies remains one of the most active areas of debate in biology. Even though a single mating is often sufficient to satisfy the fertilization needs of most females and the act of further mating incurs costs, multiple paternity within broods or clutches is a common observation in nature. Direct or indirect advantage to females is the most popular explanation. However, the ubiquity of this explanation is being challenged by an increasing number of cases for which benefits are not evident. For the first time, we test possible fitness correlates of multiple paternity in a marine turtle, an organism that has long attracted attention in this area of research. Contrary to the widespread assumption that multiple mating by female marine turtles confers fitness benefits, none were apparent. In this study, the environment played a far stronger role in determining the success of clutches than whether paternity had been single or multiple. A more likely explanation for observations of multiply sired clutches in marine turtles is that these are successful outcomes of male coercion, where females have conceded to superfluous matings as a compromise. Thus, multiple matings by female marine turtles may be a form of damage control as females attempt to make the best of a bad job in response to male harassment.

The evolutionary history of the dodo is very poorly understood. Like many avian island endemics, a high degree of morphological change associated with flightlessness and gigantism has obscured phylogenetic relationships, and historically the dodo has been linked with avian tris (originally named for its dodolike beak) is the basal member of this strongly supported clade of large, generally ground-dwelling, island endemics. Furthermore, the phylogeographic distribution of this morphologically diverse clade suggests that the dodo and the sol-Two external fossil calibrations were used in separate ML molecular clock calculations after tests found no violation of clocklike behavior (3). The analyses indicate that the dodo/solitaire and Caloenas diverged in the mid/late Eocene, around 42.6 million years ago (Ma) (95% confidence interval = 31.9 to 56.1 Ma), whereas the dodo and the solitaire separated in the late Oligocene, about 25.6 Ma (17.6 to 35.9 Ma). The latter date is biogeographically interesting as it is considerably older than the islands of Mauritius and Rodrigues. Geological evidence suggests that Mauritius emerged in a series of volcanic events, the earliest of which occurred around groups ranging from the ratites to 6.8 to 7.8 Ma, whereas Rodrigues the raptors (1). Since the mid-Geopelia cuneata did not emerge until 1.5 Ma (5). 1800s, morphological studies have Phaps chalcoptera Therefore, it seems highly unlikelinked the dodo (initially Didus in-Ocyphaps lophotes ly that the large genetic distance r> ? 77 \ 31 1 i Leucosarcia melanoleuca eptus, now Raphus cucullatus) and _ Gallicolumba beccari between the dodo and the solitaire its presumed close relative the sol-Gallicolumba tristigmata resulted from isolation on the two itaire (Pezophaps solitaria) with 1-G Gallicolumba luzonica islands. Drilling projects have esthe Columbiformes (pigeons and Otidiphaps nobilis tablished that ridges surrounding Ptilinopus melanosplM doves), but their exact position is Ptilinopussuperbus th e Mascarene Plateau were unresolved and they have been 84 91 Alectroenas madagascariensis above sea level in the late Oligoplaced in many positions within the1 00 Drepanoptila holosericea cene and have subsided slowly cosmopolitan Columbidae or in 96 Ptilinopus occipitalis thereafter (5). The similarity betheir own farmily, Raphidae, out--rl |9 Ducula arinea tween the timing of the dodo/solside the Columbidae but within 100 Ducula zoeae itaire divergence and the first Columbiformes (1, 2). To answer I Goura victoria geological evidence of land in the these questions, we extracted DNA 86r Caloenas nicobarica Mascarene island chain is striking and amplified 1.4 kb of mitochon-87 91 Pezophaps solitaria and suggests that island stepping-99 ~ 98 Raphus cucullatus drial sequence [360-base pair (bp) Didunculus strigirostrls stones may have been used before 12S rRNA and 1050-bp cyto-1ITreron vernans the two species eventually found chrome b] from 37 species of pi-9 1001 y1001 Treronaustralis their way to Mauritius and Rogeons and doves, inclu...

No abstract

Coevolution is evolution in one species in response to selection imposed by a second species, followed by evolution in the second species in response to reciprocal selection imposed by the first species. Although reciprocal selection is a prerequisite of coevolution, it has seldom been documented in natural populations. We examined the feasibility of reciprocal selection in a simple host-parasite system consisting of feral pigeons (Columba livia) and their Ischnoceran feather lice (Phthiraptera: Insecta). We tested for a selective effect of parasites on hosts with experimentally altered defenses and for a selective effect of host defense on a component of parasite escape. Previous work indicates that pigeons control lice through efficient preening, while lice escape from preening using complex avoidance behavior. Our results show that feral pigeons with impaired preening, owing to slight bill deformities, have higher louse loads than pigeons with normal bills. We use a controlled experiment to show that high louse loads reduce the survival of pigeons, suggesting that lice select for efficient preening and against bill deformities. In a reciprocal experiment, we demonstrate that preening with a normal bill selects for small body size in lice, which may facilitate their escape from preening. The results of this study verify a crucial element of coevolutionary theory by identifying likely targets of reciprocal phenotypic selection between host and parasite.