Ant distribution in relation to ground water in north Florida pine flatwoods

Longleaf pine savannas are one of the most threatened ecosystems in the world, yet are under-studied. Ants are a functionally important and diverse group of insects in these ecosystems. It is largely unknown how local patterns of species diversity and composition are determined through the interaction of this dominant animal group with abiotic features of longleaf pine ecosystems. Here we describe how an important abiotic variable, depth to water table, relates to ant species distributions at local scales. Pitfall trapping studies across habitat gradients in the Florida coastal plains longleaf pine flatwoods showed that the ant community changed with mild differences in habitat. In this undulating landscape, elevation differences were less than 2 m, and the depth to the water table ranged from \u3c 20 cm to 1.2 m. The plant species composing the ground cover were zoned in response to depth to water, and shading by canopy trees increased over deeper water tables. Of the 27 ant species that were analyzed, depending on the statistical test, seven or eight were significantly more abundant over a deep water table, eight to ten over a shallow one, and nine to eleven were not significantly patterned with respect to depth to water. Ant species preferring sites with shallow groundwater also preferred the shadier parts of the sites, while those preferring sites with deeper groundwater preferred the sunnier parts of the sites. This suggests that one group of species prefers hot-dry conditions, and the other cooler-moist. Factor analysis and abundance-weighted mean site characteristics generally confirmed these results. These results show that ant communities in this region respond to subtle differences in habitat, but whether these differences arise from founding preferences, survival, competition, or some combination of these is not known

Cicada nymphs dominate American black bear diet in a desert riparian area

American black bears are considered dependent on high-elevation forests or other montane habitats in the drylands of western North America. Black bear sign, including that of cubs, was observed throughout the summers of 2015, 2016, and 2018 along a perennial desert river in the Sonoran Desert of Arizona. We analyzed the contents of 21 black bear scats, collected from May to October of 2016 and 2018. Apache cicada nymphs (Diceroprocta apache) were the dominant food item, occurring in 90% of scats and comprising an average of 59% of scat contents. In the process of excavating these nymphs, bears created large areas of turned-over soil, a form of ecosystem engineering with potential implications for soils, vegetation, and fluvial geomorphology. Given that species distributions are shaped by physiological and ecological contexts, as well as anthropogenic legacies, it is possible that black bears once occurred more commonly in desert riparian systems prior to widespread agricultural development, hunting, and dewatering. Although more research is necessary, we suggest that desert riparian systems may be an alternative habitat for black bears. Better understanding the diet and habitat breadth of American black bears is important in the context of increasing landscape fragmentation and militarization in the U.S.-Mexican borderlands

Data for Table A1, silk removal in a natural context

These data show the presence or absence of factors associated with 29 spider webs found on Veromessor pergandei foraging columns and nest mounds. For each variable, 0 = no, 1 = yes. The statistical analysis of this data set is presented in Table A1

Data for Wilcoxon ranked sign test, head vs gaster gland assay,

Data represent worker responses to each of 3 stimuli, presented to 30 unique colonies. Paired responses to head and gaster contents were compared with a Wilcoxon ranked sign test for 28/30 unique pairs

Behavior and exocrine glands in the myrmecophilous beetle Dinarda dentata (Gravenhorst, 1806) (Coleoptera: Staphylinidae: Aleocharinae).

The nests of advanced eusocial ant species can be considered ecological islands with a diversity of ecological niches inhabited by not only the ants and their brood, but also a multitude of other organisms adapted to particular niches. In the current paper, we describe the myrmecophilous behavior and the exocrine glands that enable the staphylinid beetle Dinarda dentata to live closely with its host ants Formica sanguinea. We confirm previous anecdotal descriptions of the beetle's ability to snatch regurgitated food from ants that arrive with a full crop in the peripheral nest chambers, and describe how the beetle is able to appease its host ants and dull initial aggression in the ants

Amphotis marginata (Coleoptera: Nitidulidae) a highwayman of the ant Lasius fuliginosus.

The space occupied by evolutionarily advanced ant societies can be subdivided into functional sites, such as broodchambers; peripheral nest chambers; kitchen middens; and foraging routes. Many predators and social parasites are specially adapted to make their living inside specific niches created by ants. In particular, the foraging paths of certain ant species are frequented by predatory and kleptoparasitic arthropods, including one striking example, the nitidulid beetle, Amphotis marginata. Adults of this species obtain the majority of their nutrition by acting as a kind of "highwayman" on the foraging trails of the ant Lasius fuliginosus, where they solicit regurgitation from food laden ant-workers by mimicking the ant's food-begging signals. Employing food labeled with the radio isotope 32P, we assessed the quantities of food the beetles siphoned-off of food-laden ants, and we investigated the site preferences, behavioral mechanisms and possible morphological adaptations underlying the food kleptoparasitism of A. marginata

<i>Amphotis marginata</i> soliciting regurgitation from a worker ant of <i>M</i>. <i>rubra</i>.

<p>(Above) The beetle approaches the ant. (Below) The ant antennates and licks the beetle’s mouthparts.</p

Amphotis marginata data

Supporting data for <em>Hölldobler and Kwapich (2017)</em

Scanning electron microscopic dorsal view of the head of <i>A</i>. <i>marginata</i>.

<p>Above: Head and part of the thorax; (M) mandible: (Sc) scapus of antenna. (Below) Close up of mandibles (M), clypeus (C) labrum (Lr) and (MS) mecahosensilla.</p