Use of Patagonia's forests by hunter-gatherers remains relatively poorly understood. Regional archaeological records indicate initial forest colonization during the middle Holocene, infrequent use until late prehistory, and, even then, fairly sparse occupation, likely in conjunction with use of the adjacent steppe. Recent excavations at Río Ibáñez-6 West in Aysén, Chile, provide a new perspective for understanding the prehistoric use of Patagonian forests, particularly regarding timing of the initial occupation and the potential for development of a forest-specific adaptation. We provide chronological, lithic, archaeofaunal, and macrobotanical data that show use of the Ibáñez River valley at least a millennium earlier than previously documented. These data indicate increased dietary breadth in late prehistory, supporting the established hypothesis that the valley became a closed system at that time. From our data we develop hypotheses regarding prehistoric forest use in Aysén that have implications for the broader understanding of the suitability of the forest for prehistoric human foragers.

The trophic spectrum of both Eucinostomus entomelas and Micropogonias megalops, the two most abundant fish species in Laguna Las Guásimas, Sonora, México is described in our study. A total of 21 types of prey were identified belonging to seven taxonomic groups (Crustacea, Mollusca, Annelida, Rhodophyta, Copepoda, Echinodermata and Chordata) to analyse the feeding spectra and diet breadth. The preferred prey items of Eucinostomus entomelas (Dark-spot mojarra) were Polichaeta (index of relative importance = 46.7%), followed by bivalves (36.6%), and Luidia columbia (5.6%), while those of Micropogonias megalops (Bigeye croaker) were Portunidae (22.8%) followed by Gammaridae (20.55%) and Crustacea (18.37%). The trophic spectrum for male E. entomela was composed of Bivalvia and Polychaeta. Both predators showed low values in diet breadth (E. entomelas (Levin's index Bi = 0.14) and M. megalops (Levins's index Bi = 0.43)). The low trophic overlap (Cλ = 0.14) between predators suggests that both fish are not competing with each other for food resources in Laguna Las Guásimas.

Specialization is an important attribute of a biological control agent. The maritime pine bast scale, Matsucoccus feytaudi Ducasse (Hemiptera Matsucoccidae), is an invasive species in Southeast France and the North of Italy. Iberorhyzobius rondensis Eizaguirre (Coleoptera: Coccinellidae), is a recently described ladybird species. Both adults and larvae are predaceous, feeding on egg masses of M. feytaudi, and are strongly attracted to M. feytaudi’s sex pheromone. To evaluate the potential of I. rondensis as a biocontrol agent of the scale, we studied its niche breadth and prey range with emphasis on pine forests and hemipterans as tested prey. In this study, I. rondensis was found to achieve complete development only when fed on M. feytaudi egg masses (92.9% survival) and an artificial prey: eggs of Ephestia kuehniella Zeller (27.6% survival). From the 2nd instar onwards, complete development could be achieved using other prey species, although larvae had significantly higher mortality and slower development. In choice tests, M. feytaudi was the preferred prey. Surveys of the ladybird populations in the Iberian Peninsula revealed that it was found exclusively on Pinus pinaster Aiton, the sole host of M. feytaudi. The unusual specialization of I. rondensis, among other predaceous ladybirds, makes it an appropriate candidate for classical biological control of M. feytaudi.

The Pacific sharpnose shark Rhizoprionodon longurio is caught seasonally by inshore artisanal fisheries in the Mexican Pacific. Our study focuses on the feeding ecology of this shark species in the southern Gulf of California. The prey species obtained from stomach contents were identified and quantified, and variations between sexes and maturity stages were determined. A total of 98 stomachs were analysed during two periods (2000–2001 and 2003–2004); 64% of stomachs contained food. The trophic spectrum was composed of four cephalopod species, three crustacean species, and 13 pelagic and benthic fish species. According to the index of relative importance (%IRI), the fish Echiophis brunneus (IRI = 14.4%), Opisthopterus dovii (IRI = 12.2%) and Scomber japonicus (IRI = 9.6%) were the main prey items. Based on diversity values, IRI values and diet breadth, R. longurio is an opportunistic predator. The trophic position of R. longurio was above four in all categories, which indicates that this shark is a tertiary consumer.

Much of the ecological alteration faced by human-modified Neotropical forests can be assigned to edge effects, including the proliferation of some voracious herbivores such as leaf-cutting ants. However, the underlying mechanisms/impacts of tropical forest edge on herbivores performance and their foraging behaviour (e.g. dietary diversity) have rarely been investigated. The goal of this study was, therefore, to determine whether and how the annual diet (i.e. species richness, diversity and the relative proportion of pioneer versus non-pioneer species of plant materials) of Atta cephalotes colonies differs in the forest edge versus the interior zone of a large remnant of Atlantic forest in northeastern Brazil. Among the key results was a strong habitat effect on dietary diversity (explaining ca. 40–50% of the variation), which, in edge colonies, decreased approximately by one fourth compared to interior colonies (inverse of Simpson's index: 3.7±0.84 versus 4.99±0.95). There was a predominance of leaf fragments collected from pioneer species in the diet in both habitat (86% in edge and 80.4% in interior). Edge colonies collected proportionally more fragments from pioneer species than colonies located in the forest interior. Our results are the first to demonstrate an edge-mediated relaxation of dietary restrictions in leaf-cutting ants. These findings render robust support to previous evidence indicating the reduction of bottom-up forces as a key factor explaining both edge-induced hyper-abundance and increased herbivory of leaf-cutting ants in human-modified Neotropical landscapes.

The host location behaviour of two closely related bethylid parasitoids was investigated under laboratory conditions. Although both species of parasitoid attack the coffee berry borer (CBB) Hypothenemus hampei Ferrari, they differ in their diet breadth. In Y-tube olfactometer bioassays, we investigated the behavioural responses of Cephalonomia stephanoderis (Betrem), a parasitoid with a narrower diet breadth, and Cephalonomia hyalinipennis (Ashmead), a parasitoid with a wider diet breadth, to the coffee–CBB complex volatiles. The results revealed that the responses differed for the two species. In single- and dual-choice tests, C. stephanoderis was attracted to volatiles emitted by CBB-infested coffee berries, dust/frass and CBB immature stages, whereas C. hyalinipennis was not attracted to any cues from plant–host complex offered.