Feeding Site Selection Research Articles

Selection of summer feeding sites and food resources by female migratory caribou (Rangifer tarandus) determined using camera collars.

Migratory caribou (Rangifer tarandus) is a socioeconomically and culturally key species for northern communities in the Arctic, and most of its populations are experiencing a sharp decline. Female migratory caribou depend on the availability of summer habitat resources to meet the needs associated with lactation and the accumulation of fat reserves to survive when resources are less abundant. Because of the large scales at which habitat and resource data are usually available, information on how female migratory caribou select habitat and resources at fine scales in the wild is lacking. To document selection of summer feeding sites, we equipped 60 female caribou with camera collars from 2016 to 2018. We collected a total of 65,150 10-sec videos between June 1st and September 1st for three years with contrasted spring phenology. We determined the selection at the feeding site scale (3rd scale of Johnson) and food item scale (4th scale of Johnson) using resource selection probability functions. Wetlands were highly selected as feeding sites in June and July while they were avoided in August. Shrublands were mostly selected in July and August. At the resources scale, lichen, birch, willow, and mushrooms were the most strongly selected resources. Our results provide precise and novel information on habitat selection at feeding sites and food resources selected by female caribou in the wild. This information will help understand foraging patterns and habitat selection behavior of female migratory caribou and will contribute to the management and conservation of its declining populations.

High risk, high reward? Influence of experience level in the selection or avoidance of artificial feeding sites by Eurasian lynx

Artificial feeding of wildlife is a widespread, but controversial, management practice with many positive and negative effects. Besides the effects on the target species, it can also affect other (non-target) species by modulating interspecific interactions. Previous research showed that the presence of artificial feeding sites for bears and ungulates increases the risk of kleptoparasitism by the brown bear (Ursus arctos) on kills made by Eurasian lynx (Lynx lynx). However, it remains unknown whether lynx adjust their behaviour to the distribution of artificial feeding sites, which also attract potential prey (ungulates) for lynx. Using GPS telemetry data, we explored the spatiotemporal lynx response to such sites and studied how this response varied with experience level, i.e. between adult resident individuals ('experienced lynx') and juveniles and/or translocated individuals ('naïve lynx'). We found that lynx experience played an important role in the use of artificial feeding sites. Specifically, while both experienced and naïve lynx selected feeding sites while moving within their home range, the attraction was stronger among the naïve lynx. Considering the distribution of kill sites, naïve lynx killed prey closer to the artificial feeding sites than expected, while experienced lynx avoided them. Finally, the proximity to artificial feeding sites by experienced lynx showed an annual variation, matching the seasonal kleptoparasitism risk, with overall closer proximity to feeding sites during the winter, when bears are less active, which is also when ungulates are more concentrated around feeding sites. Our study suggests that, despite the relatively recent introduction of artificial feeding in the ecosystems, wildlife can learn to respond to the altered interactions with other species. However, this appears to be a learning process with manifold management and conservation implications. A better understanding of species interactions and space use in the context of resource manipulation is increasingly relevant as the use of anthropogenic food by wildlife is nowadays substantial and widespread across most parts of the world.

Mite damage provides refuges and affects preference and performance of a subsequent herbivorous moth

AbstractDamage by herbivores often modifies plant structure and physiology, which may change the behaviour and performance of future herbivores. Here, we studied such interactions among the major coconut pest, the mite Aceria guerreronis (Acari: Eriophyidae), and two minor pests, the mite Steneotarsonemus concavuscutum (Acari: Tarsonemidae) and the moth Atheloca bondari (Lepidoptera: Pyralidae). All these species develop in the meristematic zone of coconuts, which is difficult to access because of the small opening between the epicarp and perianth. Both mites cause necrosis on the epicarp of the nuts, which may facilitate access to the meristematic zone by caterpillars of the moth. However, the caterpillars co‐occur predominantly with A. guerreronis and not with S. concavuscutum. We show that caterpillars did not colonize nuts without mites and colonized nuts with A. guerreronis most frequently, in agreement with the openings caused by this mite and caterpillar size. When the opening between epicarp and perianth was artificially increased, caterpillars also colonized nuts without mites and nuts with S. concavuscutum. When offered a choice, caterpillars preferred nuts with easy access to the meristematic region, regardless of the presence of mites. Caterpillars performed better on the A. guerreronis‐infested nuts than on other nuts, but moth females did not preferentially oviposit in coconut bunches infested with mites. Hence, caterpillars, not adults, select suitable feeding sites within a bunch of coconuts, and A. guerreronis facilitates the infestation of coconuts by A. bondari. We discuss how damage by mites affects the relevance of A. bondari as a coconut pest.

Importance of Algarrobo Trees Prosopis flexuosa for Territory Establishment of Three Seed-Eating Passerine Species in the Central Monte Desert

In the central Monte desert in Argentina, feeding site selection by seed-eating birds and their high abundance associated with the presence of trees (particularly Algarrobos Prosopis flexuosa) are well known patterns during the breeding season, but these associations disappear during autumn and winter. In order to understand habitat selection by these bird species, we assessed the importance of Algarrobos during the defence and establishment of breeding territories in the open Algarrobo woodland of the central Monte desert for the three most common resident seed-eating birds: Ringed Warbling-finch Microspingus torquatus, Many-coloured Chaco Finch Saltatricula multicolor and Rufous-collared Sparrow Zonotrichia capensis. Despite some ecological differences between the species (e.g. nest site selection, feeding behaviour) all of them selected Algarrobos as song posts. Height, density and spatial configuration of these trees were features associated with the selection of territories. The patterns of selection we found at previously unexplored spatial scales (territory and within-territory) and associated with territorial defence, provided plausible explanations to seasonal shifts in the space use reported for central Monte desert seed-eating birds and highlight the close link between central Monte desert avifauna and Algarrobos. As in many arid regions, tall scattered trees are keystone features of the central Monte desert and management plans should be implemented in order to stop the current degradation and loss of these arid woodlands.

Habitat selection of an endangered primate, the samango monkey (Cercopithecus albogularis schwarzi): Integrating scales to prioritize habitat for wildlife management.

AimAs habitat loss continues to accelerate with global human population growth, identifying landscape characteristics that influence species occurrence is a key conservation priority in order to prevent global biodiversity loss. In South Africa, the arboreal samango monkey (Cercopithecus albogularis sp.) is threatened due to loss and fragmentation of the indigenous forests it inhabits. The aim of this study was to determine the habitat preferences of the samango monkey at different spatial scales, and to identify key conservation areas to inform management plans for this species.LocationThis study was carried out in the western Soutpansberg Mountains, which represents the northernmost population of samango monkeys within South Africa, and the only endangered subspecies (C. a. schwarzi).MethodsWe used sequentially collected GPS points from two samango monkey groups followed between 2012 and 2017 to quantify the used and available habitat for this species within the western Soutpansberg Mountains. We developed 2nd‐order (selection of ranging area), 3rd‐order (selection within range), and 4th‐order (feeding site selection) resource selection functions (RSFs) to identify important habitat features at each scale. Through scale integration, we identified three key conservation areas for samango monkeys across Limpopo Province, South Africa.ResultsHabitat productivity was the most important landscape variable predicting probability of use at each order of selection, indicating the dependence of these arboreal primates on tall‐canopy indigenous forests. Critical habitat across Limpopo was highly fragmented, meaning complete isolation between subpopulations is likely.Main conclusionsUnderstanding the habitat characteristics that influence samango monkey distribution across South Africa is crucial for prioritizing critical habitat for this species. Our results indicated that large, contiguous patches of tall‐canopy indigenous forest are fundamental to samango monkey persistence. As such, protected area expansion of large forest patches and creation of forest corridors are identified as key conservation interventions for this species.

Selection of Estuarine Feeding Habitats by Snowy and Great Egrets in the Great Marsh Estuary, Northeastern Massachusetts, USA

The feeding habitats of Great (Ardea alba) and Snowy (Egretta thula) egrets at the Great Marsh in Northeastern Massachusetts, USA, were characterized through field observations over two years during the breeding seasons of 2012 and 2013. Both species were from a large breeding colony making a daily commute to the Great Marsh for foraging. Habitats at the Great Marsh were delineated as marsh pools, the vegetated marsh, impoundments, open water, tidal flats, and tidal creeks and ditches. Observations (45 counts in 2012 and 48 in 2013) consisted of recording the number of birds, behavior (feeding or not), habitat, and the time of observation and relating these observations to the tidal cycle. The preferred feeding habitats of Snowy Egrets were in marsh pools and along the edges of large impoundments. The preferred feeding habitats of Great Egrets were on the marsh platform, particularly at high tides, and marsh pools. An analysis of physical characteristics with locations of feeding sites revealed no consistent patterns. Certain sites would occasionally support large numbers of feeding Great and Snowy egrets one day only to be ignored the next day at the same tide. The results suggest that Great and Snowy egrets are opportunistic in their selection of feeding sites at the Great Marsh. A future of wetter marshes might provide more feeding opportunities for Great and Snowy egrets, at least in the short-term.

Central place foraging in a human‐dominated landscape: how do common cranes select feeding sites?

Human infrastructure and disturbance play an important role when animals select resources in human‐modified landscapes. Theory predicts that animals trade food intake against costs of movement or disturbance to optimize net energy gain and fitness, but other necessary resources may also constrain the decisions, e.g. when animals repeatedly need to return to a central location, such as a nest, waterhole or night roost. Central place foraging theory states that the probability of occurrence of an animal decreases with the distance to the central location while selectivity for food items or foraging sites providing high net energy gain should increase with distance. We studied foraging patterns of common cranes Grus grus feeding in an agricultural landscape adjacent to a wetland to which they return for night roost. We used availability of spilled grains on harvested fields and distance to human settlement as proxy for site quality (i.e. increased likelihood of increased net energy gain with increased food availability and less disturbance). As predicted by theory, our results clearly show that cranes were more likely (more than twice as high resource selection function scores) to select foraging sites close to roosts. However, contrary to predictions, the selection of high quality sites in terms of high food availability decreased with distance to roost sites. Nevertheless, our results indicate that cranes were more likely to select sites with low risk of human disturbance far from roost sites, and were more tolerant to disturbance close to roost sites. How different species respond to the local and environmental conditions will increase the understanding of the species’ resource requirement, and also where in the landscape to prioritize conservation or management actions (e.g. mitigation of human disturbance and crop damage prevention to sustain agricultural production).

Effect of the eucalypt lerp psyllid Glycaspis brimblecombei on adult feeding, oviposition‐site selection, and offspring performance of the bronze bug, Thaumastocoris peregrinus

AbstractOviposition‐site selection may be greatly affected by competitive plant‐mediated interactions between phytophagous insects but these interactions have been poorly investigated on trees. Here, we evaluated the potential interaction between two invasive pests of Eucalyptus trees, the red gum lerp psyllid, Glycaspis brimblecombeiMoore (Hemiptera, Sternorrhyncha: Aphalaridae), and the bronze bug, Thaumastocoris peregrinusCarpintero et Dellapé (Heteroptera: Thaumastocoridae). We assessed the effect of the co‐occurrence of G. brimblecombei on the selection of feeding and oviposition sites by T. peregrinus females using dual‐choice bioassays. We compared developmental time and survival of the first instar of nymphs reared on healthy Eucalyptus tereticornisSmith (Myrtaceae) leaves and on leaves infested with the lerp psyllid, either with or without lerps (i.e., white conical sweet‐tasting structures, secreted during the nymphal stage). Bronze bug females prefer to oviposit on lerp‐carrying leaves but we found no difference in feeding preference when compared to healthy leaves. Infestation with the lerp psyllid hampered nymphal performance in terms of developmental time and survival, although the presence of lerps reverted the effect in survival and shortened the duration of the initial instar. These results display an interaction between these two insect species that affects both the oviposition preference of T. peregrinus females and the nymphal performance. Although there seems to be a discrepancy between mother preference and offspring performance, feeding on the lerps may prove beneficial to the offspring under long‐term conditions and multiple infestation by other pests and diseases.

Sclerenchymatous ring as a barrier to phloem feeding by Asian citrus psyllid: Evidence from electrical penetration graph and visualization of stylet pathways

Asian citrus psyllid (Diaphorina citri) feeding behaviors play a significant role in the transmission of the phloem-limited Candidatus Liberibacter asiaticus (CLas) bacterium that causes the economically devastating citrus greening disease. Sustained phloem ingestion by D. citri on CLas infected plants is required for pathogen acquisition and transmission. Recent studies have shown a fibrous ring of thick-walled sclerenchyma around the phloem in mature, fully expanded citrus leaves that is more prominent on the abaxial compared with the adaxial side. The composition and thickness of this fibrous ring may have an important role in selection of feeding sites by D. citri based on leaf age and leaf surface, which in turn can affect pathogen acquisition and transmission. We measured feeding behavior using electrical penetration graph (EPG) recordings of individual D. citri adults placed on abaxial or adaxial surfaces of young or mature Valencia orange leaves to study the role of the sclerenchymatous ring in modifying D. citri feeding behavior. Feeding sites on the same leaf tissues were then sectioned and examined by epifluorescence microscopy. The duration of phloem ingestion (E2 waveform) by psyllids was significantly reduced on mature compared with young leaves, and on abaxial compared with adaxial leaf surfaces. The longest duration of phloem ingestion was observed from psyllids placed on the adaxial side of young leaves that had the least developed sclerenchyma. Bouts of phloem salivation (E1 waveform), however, were significantly longer on mature leaves compared with young leaves. D. citri adults made consecutive phloem feeding attempts (bouts) on the abaxial side of mature leaves and those bouts resulted in unsuccessful or shorter periods of phloem ingestion. Adults also made more frequent and longer bouts of xylem ingestion on mature leaves compared with adult psyllids placed on young leaves. Epifluorescence microscopy showed that the fibrous ring in young leaves was thinner and autofluoresced in red whereas the ring in mature leaves was thicker and autofluoresced in blue, indicating changes in structure and composition (e.g., lignification) of sclerenchyma correlated with leaf age. Our results support the hypothesis that the presence of a thick, well-developed fibrous ring around phloem tissues of mature leaves acts as a barrier to frequent or prolonged phloem ingestion by D. citri from citrus leaves. This may have an important role in limiting or preventing CLas acquisition and/or transmission by D. citri, and could be used for identification and development of resistant citrus cultivars.

Microhabitat selection for caching and use of potential landmarks for seed recovery by a neotropical rodent

AbstractScatter‐hoarding rodents may interact with the structural characteristics of their environment in several ways: by seeking dense areas inside the forest for protection during seed handling, by caching seeds close to objects that might be used as visual cues for seed recovery or by hiding themselves inside refuges such as burrows. We investigated the use of structural characteristics of the forest by a scatter‐hoarder rodent (the Azara's agouti, Dasyprocta azarae) in the Brazilian Araucaria Forest. We evaluated the selection of microhabitat characteristics for feeding or caching seeds, and the selection of potential landmarks for increasing seed recovery rates. For that, we followed threaded seeds of Araucaria angustifolia (Araucariaceae) and also placed artificial caches in the forest. We predicted that agoutis (1) select feeding and caching sites whose microhabitat characteristics potentially enhance protection against predators, (2) hoard seeds preferentially near potential landmarks and (3) find artificial caches placed near potential landmarks more frequently than caches placed away (<0.5 m) from any landmark. As expected, agoutis significantly selected feeding and caching sites with greater herbaceous cover, closer to tree trunks, and with higher tree density compared to randomly selected sites. Considering potential landmarks, agoutis not only selected sites near to fallen logs and treelets for caching but also preferred the latter for immediate seed consumption. Moreover, seeds buried near treelets were recovered more frequently than seeds cached near fallen logs, tree trunks or exposed rocks. The proximity of potential landmarks, however, did not influence seed removal from artificial caches, suggesting that visual cues do not enhance seed location by naive foragers. Our conclusions are: (1) agoutis transport seeds to potentially safer places for immediately consuming or burying them; (2) fallen logs and treelets are potential visual cues for seed recovery; and (3) naive foragers seem to use mainly olfactory cues for seed detection.

Effects of timber harvesting on Arundinaria spanostachya bamboo and feeding-site selection by giant pandas in Liziping Nature Reserve, China

Timber harvesting can alter understory plant diversity, abundance and composition, and in turn shape behaviors of a variety of animals. By far, little is known about the effects of timber harvesting on bamboo understory and feeding-site selection by giant pandas. Here, we investigated differences in crude protein, crude fat and tannin in Arundinaria spanostachya and feeding-site selection by giant pandas in primary and secondary forests in Liziping Nature Reserve, China. One hundred and twenty plots were established in the wild, including 30 feeding-site plots and 30 control plots in primary and secondary forests respectively. The results indicated that after timber harvesting, bamboo grows denser in secondary forests, with decreased crude protein content and increased tannin content, especially in leaves. Giant pandas exhibited distinct feeding-site selection patterns in primary and secondary forests. In primary forests, giant pandas appear to randomly forage bamboo across age groups but feed more on perennial bamboo culms (⩾3yr) and less on annual bamboo culms (⩽1yr) in secondary forests. Above findings highlight the importance of conserving the primary forests in the Xiaoxiangling Mountains, and suggest that training and acclimatization of captive individuals for release should be as possible as can conducted in primary forests without human disturbance.

Effect of terrain heterogeneity on feeding site selection and livestock movement patterns

Feeding site selection is a critical part of livestock foraging that can constrain and/or increase the choices available during diet selection. When livestock choose new feeding sites, vegetation and nutrient profiles can differ from other areas, especially in heterogeneous environments with rugged terrain. Correspondingly, livestock should remain longer in feeding sites in rugged heterogeneous pastures than in homogeneous pastures where animals may alternate among feeding sites to facilitate diet mixing and to prevent satiation. The objective of this study was evaluate how terrain and corresponding heterogeneity may affect the sequence and pattern of feeding site selection of free-roaming livestock. Grazing patterns of mature cows were evaluated on six ranches located in Arizona, Montana and New Mexico. In total, 11–19 cows were tracked for 1–3-month periods at each ranch by using global positioning system (GPS) collars. Positions were recorded at 10- or 15-min intervals and used to identify where cows grazed during the early morning (0500 hours to 1000 hours). Pastures (336–9740 ha) at each ranch were divided into seven to nine sections (48–1082 ha) as an indicator of feeding sites. Classification was based on cattle density and topographical and vegetation types. Sequences of daily section selection were evaluated using transition matrixes. For all ranches, the sequence of section selection differed from what would be expected by chance, indicating that the section selected on the following day depended on the section selected on the previous day. For ranches with relatively gentle terrain, cattle selected different feeding sites ~70% of the tracking period. In contrast, cows at the ranch with the largest pasture and enclosing both mountainous and gentle terrain stayed in the same feeding site for over 10 successive days for 42% of the tracking period. Smaller pastures with only mountainous terrain were intermediate. Cows grazing gentle topography and relatively homogeneous vegetation alternated among feeding sites (sections in the present study) more frequently than cows grazing pastures with more rugged topography and more heterogeneous vegetation. This pattern could help livestock mix forages and select a more diverse diet.

Using Stochastic Gradient Boosting to Infer Stopover Habitat Selection and Distribution of Hooded Cranes Grus monacha during Spring Migration in Lindian, Northeast China

The Hooded Crane (Grus monacha) is a globally vulnerable species, and habitat loss is the primary cause of its decline. To date, little is known regarding the specific habitat needs, and stopover habitat selection in particular, of the Hooded Crane. In this study we used stochastic gradient boosting (TreeNet) to develop three specific habitat selection models for roosting, daytime resting, and feeding site selection. In addition, we used a geographic information system (GIS) combined with TreeNet to develop a species distribution model. We also generated a digital map of the relative occurrence index (ROI) of this species at daytime resting sites in the study area. Our study indicated that the water depth, distance to village, coverage of deciduous leaves, open water area, and density of plants were the major predictors of roosting site selection. For daytime resting site selection, the distance to wetland, distance to farmland, and distance to road were the primary predictors. For feeding site selection, the distance to road, quantity of food, plant coverage, distance to village, plant density, distance to wetland, and distance to river were contributing factors, and the distance to road and quantity of food were the most important predictors. The predictive map showed that there were two consistent multi-year daytime resting sites in our study area. Our field work in 2013 using systematic ground-truthing confirmed that this prediction was accurate. Based on this study, we suggest that Lindian plays an important role for migratory birds and that cultivation practices should be adjusted locally. Furthermore, public education programs to promote the concept of the harmonious coexistence of humans and cranes can help successfully protect this species in the long term and eventually lead to its delisting by the IUCN.

Maternal influence on feeding site selection of male and female lambs

We conducted an experiment to determine whether early-life social learning of feeding site selection in lambs was sex-specific. Sixteen ewes and their new born lambs were used in a controlled experiment. Eight ewe–lamb pairs included a male lamb and the remaining eight a female lamb. All pairs were individually exposed to an experimental arena containing a safe and unsafe artificial feeding site (SFS, UFS) each consisting of nine bowls which contained either ground Bermuda grass hay (SFS) or ground alfalfa hay (UFS). The bowls in UFS were surrounded by bright orange traffic cones (visual cues). Half the ewes were trained with controlled electric shock to avoid UFS. Thus, pairs were randomly assigned to: (1) shock aversion training (SAT) to mothers of male lambs (MS); (2) SAT to mothers of female lambs (FS); (3) no aversion training (NAT, control) to mothers of male lambs (MC); and (4) NAT (control) to mothers of female lambs (FC). None of the lambs were subjected to SAT. During training, testing, extinction, and retraining ewe–lamb pairs were exposed to the arena together. Ewes were then removed from the experiment and two additional extinction phases were conducted with weaned lambs alone. Fear conditioning elicited UFS avoidance of both the trained ewes (means±s.e.m. % times observed in UFS during testing phase: FC=95.3±1.70; MC=94.4±4.87; FS=1.6±1.63; MS=0 ±0; P<0.01) and their naïve lambs (FC=83.8±6.07%; MC=76.6±6.56%; FS=30.4±7.90%; MS=33.9±9.23%; P<0.01). UFS avoidance in lambs occurred regardless of sex and tended to persist after weaning (% times observed in UFS during 1st post-weaning extinction phase: FC=92.6±4.50%; MC=89.8±6.09%; FS=45.1±10.57%; MS=43.5±10.42%; P=0.06). Fear conditioning in mothers appeared to alter sex-related differences in mother–infant behavioral synchrony by increasing and decreasing feeding synchrony of male and female lambs, respectively (FC: r=0.52, P<0.01; MC: r=−0.02, P=0.86; FS: r=0.14, P=0.26; MS: r=0.46, P<0.01). During the extinction phase mothers of ram lambs were observed feeding more often (FC=85.0±2.33%; MC=92.7±1.45%; FS=47.3±8.81%; MS=72±5.68%; P=0.02) and standing less often than ewes with daughters (FC=7.3±2.40%; MC=2.7±0.83%; FS=39.3±9.04%; MS=18.0±5.29%; P=0.06). This study suggests that social conditioning at an early age could be a viable tool to induce learning of feeding site avoidance in female and male lambs alike.

Daily feeding site selection of cattle and sheep co-grazing a heterogeneous subtropical grassland

Effective management of livestock grazing on heterogeneous subtropical grasslands requires understanding the relative role played by factors that determine spatial distribution patterns of animals. We conducted a 2year study at a site in Corrientes, Argentina, to characterize seasonal patterns of feeding site selection of cattle and sheep co-grazing the same pastures. Livestock were fitted with GPS collars and monitored for 2weeks in fall, winter, spring, and summer of two consecutive years beginning in 2009. Maps of vegetation units, topography, and facilities were included as layers in a GIS of our study site which, in addition to livestock location data, were used to analyze daily feeding site selection patterns of both livestock species. The k-select multivariate method used for this analysis suggested that 21% of the variation in daily feeding site selection of both cattle and sheep could be explained by vegetation-related variables. Lesser amounts of variation were explained by weather-related variables, topography, and distance to drinking water and shade. In general, cattle tended to select lower elevation sites dominated by taller grasses, whereas sheep tended to select higher elevation sites with steeper slopes dominated by short grasses. Both cattle and sheep appeared to adapt to year-to-year changes in vegetation and rainfall by adjusting their feeding site selection and either expanding or contracting the area explored while grazing in a day. Spatial overlap between species remained low throughout the study. Cattle and sheep appeared to exhibit complementary adaptive feeding strategies at this site. Subtropical grassland areas with heterogeneous vegetation cover could be utilized more efficiently with co-grazing of livestock species with contrasting body size and dietary habits.

Feeding Site Selection by Frog-Biting Midges (Diptera: Corethrellidae) on Anuran Hosts

A critical challenge of obtaining a blood meal resides in selecting a feeding site at the host. We investigate the feeding sites of species of frog-biting midges (Corethrella spp) on tungara frogs, Engystomops pustulosus (Cope), and two species of treefrogs, Dendropsophus ebraccatus (Cope) and Dendropsophus microcephalus (Cope). To investigate the differences in midge feeding sites, we performed field observations, histological sections of the frogs and examined the mouthparts of the midges. Feeding sites are predicted by the vascular properties of the skin in different body areas of the frogs. According to optimal foraging theory, the midges should feed on host body areas that maximize blood intake. Contrary to optimal foraging theory predictions, however, their feeding sites correspond to body areas with high intensity host defensive behavior.

The effect of microhabitat feeding site selection on aphid foraging and predation risk

Organisms attempt to optimize foraging by maximizing resource acquisition while minimizing predation risk. Aphids (group-living, phloem-feeding insects) routinely change feeding positions and interact with predators and parasites at the single-leaf scale. Here, we assess the life history and predation risk consequences of within-leaf feeding site choices in pea aphids in response to different natural enemies. First, three-chambered clip cages were used to isolate first instar aphids anterior and posterior to a centrally feeding adult on the underside of a single broad bean leaf. Development time to adulthood did not differ between feeding sites, nor did fecundity within the first 24 h of reproduction. Second, we recorded the frequency and latency of natural enemy attacks on aphids adhered to three leaf sites, matching those of the clip cage experiment, on the underside of a single leaf. Aphids feeding nearest the leaf petiole were at greatest risk of predation by a foliar foraging coccinellid predator, Hippodamia convergens, but not by a parasitoid wasp, Aphidius ervi. Thus, feeding nearer the leaf petiole provided no individual life history benefits and exposes the aphid to increased predation risk. We further discuss the notion that feeding at these sites may provide inclusive fitness benefits for colony mates via alarm signaling and subsequent decreased predation success.

Competitor avoidance drives within‐host feeding site selection in a passively dispersed herbivore

Evolutionary theory predicts that ovipositing females that can actively disperse should select hosts that increase offspring performance. However, for organisms that are exclusively passively dispersed, feeding site selection is possible only at the within‐host level. This is particularly important for their offspring, which have strong temporal and spatial dispersal constraints within a host. Such constraints are probably magnified by tissue quality heterogeneity caused by competing herbivores. We investigated within‐host feeding site selection of passively dispersed neonates of a sessile herbivore, the hemlock woolly adelgid (Adelges tsugae Annand), when it shares its eastern hemlock (Tsuga canadensis Carrière) host with another sessile herbivore, the elongate hemlock scale (Fiorinia externa Ferris). Within‐host feeding site selection was studied (a) at the shoot level (with or without F. externa) using choice tests, and (b) at the needle level by scoring insect presence in field surveys. Adelges tsugae avoided F. externa‐colonised foliage in both the choice tests and field surveys. As A. tsugae has no efficient predators or parasitoids in the study area, we conclude that our results are due to the presence of the competing herbivore. Although A. tsugae cannot actively disperse among hosts, we showed that within‐host feeding site selection is an important mechanism to minimise the co‐occurrence with a competing herbivore that has known negative impacts on A. tsugae population densities. Studying within‐host feeding site selection in a multiple‐species context could assist in understanding and predicting the impact of destructive pests such as A. tsugae and the interactions with their novel hosts.

Sex Differences in Piercing–Sucking Sites on Leaves of Ligustrum lucidum (Oleaceae) Infested by the Chinese White Wax Scale Insect, Ericerus pela (Chavannes) (Hemiptera: Coccidae)

The type of host tissues and cells ingested by piercing and sucking insects greatly affects their nutrient intake, which may subsequently affect insect fitness. This study describes the sex differences in feeding site selection between male and female nymphs of the Chinese white wax scale insect (CWWS), Ericerus pela (Chavannes), feeding on leaves of the Chinese privet, Ligustrum lucidum. Our data showed that the stylet tips of female nymphs terminated in the phloem sieve elements of main or lateral veins, while those of male nymphs terminated in the palisade parenchyma. We concluded that female nymphs fed from sieve elements and males fed from parenchyma cells. The potential impact of these feeding patterns was discussed in relation to the selection of a site for attachment, nutrient acquisition, and mouthpart stretching mechanism. Among these factors, selection of a site for attachment and mouthpart stretching mechanism may be the main cause of sex differences in feeding sites between female and male nymphs of CWWS.

Seasonal feeding site selection of the Nonggang Babbler (&lt;I&gt;Stachyris nonggangensis&lt;/I&gt;) in Nonggang, Guangxi, China

We investigated the feeding sites of the Nonggang Babbler (Stachyris nonggangensis) during three time periods (July-September, 2010; November-December, 2010; January-February, 2011) in Nonggang National Nature Reserve, Guangxi, China with the line transect method and sampling method. Principal component analysis of the data identified that the feeding sites in the rainy season were dominated by factors consisting of tree layer, the layer of fallen leaves and the herb layer; whereas the feeding sites in the dry season were dominated by factors dependant on terrain, herb layer and shrub layer. The results of a circular distribution analysis showed that the Nonggang Babbler preferred feeding sites with a gentle slope in both the rainy season and dry season. The tests of differences of the variables between used and control plots indicated that with low arbor coverage in the rainy season, whereas with a low slope position, high shrub and thick fallen leaves in the dry season. In comparison with the rainy season, the feeding sites in the dry season tended to be at lower altitude, to have a lower slope position, lower grass coverage, and to be covered with a larger and thicker bed of fallen leaves. A logistic regression analysis suggested that altitude, slope, and shatter cover were the most important factors influencing feeding site selection in the rainy season. Slope position, arbor cover, grass cover, and the thickness of the shatter cover were the most important factors influencing feeding site selection in the dry season.