Long-term monitoring of margays (Leopardus wiedii): Implications for understanding low detection rates

Population assessments of wide-ranging, cryptic, terrestrial mammals rely on camera trap surveys. While camera trapping is a powerful method of detecting presence, it is difficult distinguishing rarity from low detection rate. The margay (Leopardus wiedii) is an example of a species considered rare based on its low detection rates across its range. Although margays have a wide distribution, detection rates with camera traps are universally low; consequently, the species is listed as Near Threatened. Our 12-year camera trap study of margays in protected broadleaf forest in Belize suggests that while margays have low detection rate, they do not seem to be rare, rather that they are difficult to detect with camera traps. We detected a maximum of 187 individuals, all with few or no recaptures over the years (mean = 2.0 captures/individual ± SD 2.1), with two-thirds of individuals detected only once. The few individuals that were recaptured across years exhibited long tenures up to 9 years and were at least 10 years old at their final detection. We detected multiple individuals of both sexes at the same locations during the same survey, suggesting overlapping ranges with non-exclusive territories, providing further evidence of a high-density population. By studying the sparse annual datasets across multiple years, we found evidence of an abundant margay population in the forest of the Cockscomb Basin, which might have been deemed low density and rare, if studied in the short term. We encourage more long-term camera trap studies to assess population status of semi-arboreal carnivore species that have hitherto been considered rare based on low detection rates.

An atypical mating system in a neotropical manakin

Most of the diversity in the mating systems of birds and other animals comes at higher taxonomic levels, such as across orders. Although divergent selective pressures should lead to animal mating systems that diverge sharply from those of close relatives, opportunities to examine the importance of such processes are scarce. We addressed this issue using the Araripe manakin ( Antilophia bokermanni ), a species endemic to a forest enclave surrounded by xeric shrublands in Brazil. Most manakins exhibit polygynous lekking mating systems that lack territoriality but exhibit strong sexual selection. In sharp contrast, we found that male Araripe manakins defended exclusive territories, and females nested within male territories. However, territoriality and offspring paternity were dissociated: males sired only 7% of nestlings from the nests within their territories and non-territorial males sired numerous nestlings. Moreover, female polyandry was widespread, with most broods exhibiting mixed paternity. Apparently, territories in this species function differently from both lekking arenas and resource-based territories of socially monogamous species. The unexpected territoriality of Araripe manakins and its dissociation from paternity is a unique evolutionary development within the manakin clade. Collectively, our findings underscore how divergences in mating systems might evolve based on selective pressures from novel environmental contexts.

Battle of the sexes: a multi-male mating strategy helps lionesses win the gender war of fitness

In species exhibiting infanticide by males, females lose out with high stakes and should adopt preemptive mechanisms, pitching the genders in an evolutionary arms race for maximizing fitness. African lions remain a quintessential model of this gender war, with a coalition of males gaining temporary but exclusive breeding rights over a female group after killing all cubs of former males. However in Asiatic lions, now found as a single population in Gir forests, India, adults live in same-sex groups that interact primarily for mating. Intensive monitoring of 70 adult lions revealed that female groups (n = 9) used exclusive territories, whereas male ranges (n = 11 coalitions) overlapped at areas of intense female use. A social network of mating events (n = 76) indicated that lionesses mated with multiple rival coalitions before conceiving. These neighboring coalitions, although hostile to each other were tolerant toward the same litters, suggestive of confused paternity among them. Given a land-tenure system where lionesses encounter many males capable of killing unfamiliar cubs, multi-male mating buffers cub infanticide and likely diversifies paternal lineages in litters. Consequently, infanticide was observed only when “new” males invaded a female group’s territory. An age-based mate choice was observed in lionesses: maiden breeders chose males having highest range overlaps, whereas experienced females selected peripheral males. The intergender spacing patterns and resultant sexual strategies of lions differ in Asia and Africa probably because of contrasting resource availability, highlighting behavioral plasticity within species inhabiting diverse eco-regions. By mating with multiple males, lionesses safeguard their investments and outdo the males in the war of fitness.

Kinkajou: the tree-top specialist

Kinkajous have evolved a suite of unique adaptations not seen in other Carnivores, helping them thrive in the canopies of neotropical forests. They have a prehensile tail and reversible hind feet to help them climb trees, and large eyes and scent glands to help them navigate complex tropical canopies at night. By sticking to the treetops at night kinkajous have very few potential predators, and this frees them from the need move in large groups for protection, as seen in most diurnal primates. Instead, kinkajous live in small social groups that forage for fruits and flowers mostly as singletons, but reunite at large feeding or sleeping trees. Females defend exclusive territories against each other while males form small coalitions to defend larger areas that overlap with multiple females. Fruit comprises 90-99% of their diet, making kinkajous one of the most frugivorous mammals on earth, and an important seed disperser.

Developing Models of a Band Society

Beginning with the assumption that Paleoindian peoples were organized into hunter-gatherers bands, archaeologists have developed prehistoric settlement models based upon ethnographically known hunter-gather groups. One such model created by Lewis Binford identified two general site types called base camps and work camps. Archaeologists have concluded that prehistoric hunter-gatherers exhibited a settlement mobility organized around resource zones such as rivers, waterholes, lakes, diverse ecotones (which provided a greater variety of plants and animals), and stone quarries from which they could obtain raw materials to fashion tools. We presume that the early prehistoric bands around Tampa Bay were territorial or at least occupied exclusive territories. Traditionally, the difference between Paleoindian and Archaic settlement patterns focused on the alleged readaptation that occurred between the Pleistocene and Holocene. More recently, though, Cleland’s focal/diffuse model notes a change from specialized adaptations geared toward similar resources to an economy focused on varied or scattered resources.

Space Partitioning Without Territoriality in Gannets

Colonial breeding is widespread among animals. Some, such as eusocial insects, may use agonistic behavior to partition available foraging habitat into mutually exclusive territories; others, such as breeding seabirds, do not. We found that northern gannets, satellite-tracked from 12 neighboring colonies, nonetheless forage in largely mutually exclusive areas and that these colony-specific home ranges are determined by density-dependent competition. This segregation may be enhanced by individual-level public information transfer, leading to cultural evolution and divergence among colonies.

Competitive Pressure and the Adoption of Complementary Innovations

Liberalization of the European automobile distribution system in 2002 limits the ability of manufacturers to impose vertical restraints, leading to a substantial increase in competitive pressure among dealers. We estimate an equilibrium model of profit maximization to evaluate how dealers change their innovation adoption strategies following the elimination of exclusive territories. Using French data we evaluate the existence of complementarities between the adoption of software applications and the scale of production. Firms view these innovations as substitutes and concentrate their effort in one type of software as they expand their scale of production. Results are robust to the existence of unobserved heterogeneity. (JEL D24, K21, L21, L22, L62, O32)