Foraging mode of Australolacerta rupicola (FitzSimons, 1933) (Sauria: Lacertidae): evidence of seasonal variation in an extremely active predator?

Foraging mode of the endemic Soutpansberg rock lizard (Australolacerta rupicola) was determined by (1) measuring the number of movements per minute (MPM) and the percentage time spent moving (PTM); and (2) analysing faecal samples. Furthermore, these criteria were related to diet composition, proportion of attacks initiated while moving and foraging substrate. The results are discussed in comparison to the foraging modes of 20 other lacertid species. Values for MPM and PTM as well as faecal analysis indicate an active foraging strategy for A. rupicola. Although rock living, this species mostly forages in leaf litter where it is well camouflaged while actively searching for sedentary prey. Even in comparison to other active foragers of the family Lacertidae, A. rupicola displays the prototypic behaviour of a widely foraging lizard with very high PTM and very low MPM.     

A method of obtaining dietary data for slow worms (Anguis fragilis) by means of non‐harmful cooling and results from a Danish population

Diet composition of slow worms (Anguis fragilis) from a Danish population was recorded from May to September 2006. Slow worms were maintained in cool conditions (at 8°C) for a maximum of 126 h, which made approximately half of the animals regurgitate. The method worked equally well on juveniles and adults. The regurgitations revealed that the slow worms preyed on small snails, slugs, pill millipedes (Glomeris marginata), earthworms and Lepidoptera larvae. There were seasonal changes in taxon composition of the diet but no ontogenetic or sex‐related differences. The food quality of selected prey types was tested on juveniles in a laboratory experiment. Mealworms gave a significantly lower gain in mass and snout–vent length than slugs, earthworms and a mix of all three prey types. A supplementary experiment revealed that slow worms from the present population completely rejected mealworms as prey. Earthworms seemed to be nutritionally inferior to molluscs.     

Gastrointestinal helminths of eleven species of Emoia (Squamata: Scincidae) from Papua New Guinea

Four hundred and forty‐six individuals representing 11 species of Emoia (Scincidae), E. atrocostata, E. battersbyi, E. caeruleocauda, E. impar, E. jakati, E. kordoana, E. longicauda, E. obscura, E. pallidiceps, E. physicae and E. popei, collected in Papua New Guinea were examined for helminths. Two species of Cestoda (Adenobrechmos greeri, Cylindrotaenia hickmani); five species of Digenea (Mesocoelium monas, Paradistomoides gregarium, Saurokoilophilia kinsellai, Spelotrema brevicaeca, Zeylanurotrema sphenomorphi); 14 species of Nematoda, (gravid individuals of Abbreviata oligopapillata, Hedruris hanleyae, Kreisiella chrysocampa, Maxvachonia adamsoni, Meteterakis crombiei, Parapharyngodon maplestoni, Physaloperoides milnensis, Pseudoreticularia dipsarilis, Raillietnema nanus, Skrjabinodon sp. 1, Skrjabinodon sp. 2 and larvae (in cysts) of Abbreviata sp., Acuariidae gen. sp., and Riticulariidae gen. sp.) were found. The mean helminth species richness for infected skinks was 6.4±4.7 SD (range 1–14 species). Fifty‐three new host records are reported.     

Basking behaviour in two sympatric herbivorous lizards (Liolaemidae: Phymaturus) from the Payunia volcanic region of Argentina

We studied several aspects of the thermal biology of two coexisting saxicolous species of the genus Phymaturus (Liolaemidae) at the Payunia, a volcanic region in Argentina where harsh conditions prevail. We marked individuals in grids and assessed the environmental conditions when the individuals showed their maximum activity (i.e. when more than 50% of marked individuals were active), the time spent basking, and the postural behaviour in relation to different cloudiness conditions. We found that temperatures recorded when the species exhibit their peaks of activity were higher for Phymaturus payuniae, the smaller species, during the summer at one of the three studied sites. Phymaturus roigorum exhibited the longest basking periods, but during these longer periods cloudy conditions prevailed. Both species adopted a head-up posture when conditions were sunny and a head-down posture when under cloudy conditions. This is the first contribution where thermal aspects of two sympatric species of Phymaturus are evaluated.     

The varied foraging mode of the subtropical eublepharid gecko Goniurosaurus kuroiwae orientalis

Insectivorous lizards usually employ one of two foraging modes, ambush ‘sit-and-wait’ or active ‘widely foraging’, but in the Gekkonomorpha the situation has been unclear. Therefore we quantified the foraging mode of the eublepharid gecko Goniurosaurus kuroiwae orientalis on Tokashikijima near Okinawajima, Japan, in September 1999. The taxon is rare, endangered and protected. On the selected semi-urban study site the gecko was confirmed as a nocturnal cursorial gecko, which also ascends trees up to 1.8 m. Foraging regimes of marked individuals, during repeated 30-min observation periods, could vary from immobility throughout, to active locomotion 84% of the time. Foraging mode was not significantly affected by sex, body length, mass or state of tail regeneration of the individuals, or by the timing of the observation. In males, at higher temperatures single moves became longer, while time allocated to moving was stable. In both sexes longer observation bouts included longer sitting pauses, which, given stable move duration, reduced the share of time spent moving and the moves per minute. Goniurosaurus kuroiwae orientalis averaged moving during 23% of the time, moving 0.39 times per minute, the moves lasting 77 s and the pauses lasting 745 s. Compared to other geckos, G. k. orientalis may be defined as a widely foraging animal, despite its mixed behaviour. This result supports the definition of the Eublepharidae as widely foraging and is compatible with two hypotheses, that early Gekkonomorpha were widely foraging or that they had an intermediate, undefined, foraging mode.     

Foraging behaviour of three sphaerodactylin geckos on Trinidad and Tobago (Sauria: Gekkonomorpha: Sphaerodactylini: Gonatodes)

Taxonomic families of insectivorous lizards are usually characterized by one of two distinct foraging modes, namely ambush ‘sit-and-wait’ or active ‘widely foraging’. In the Gekkonomorpha the situation has been unclear and in dispute, and among these, that in the Sphaerodactylini is almost unreported. We, therefore, examined the foraging mode of three sphaerodactylin species on Trinidad and Tobago, in May—June 2000 (totalling 72 individuals, observations averaging 23.6 min/individual). In terms of species averages, Gonatodes vittatus, G. humeralis and G. ocellatus all moved for only 1.6–3.55% of observation time (PTM, percent time moving), and switched from sitting to locomoting only 0.18–0.36 times per minute (MPM, moves per minute). The genus thus is a strict sit-and-wait forager. In G. vittatus, the foraging mode was unaffected by sex or habitat structure. In all three species, foraging mode was unaffected by the time of day or air temperature. In G. humeralis, foraging activity (PTM or MPM) correlated with light intensity in the forest within a population (at least MPM) and among populations (at least PTM). Among the three species, too, foraging activity (PTM and MPM) ranked with light intensity during sampling. In all three species, the geckos perched for 68–76% of the time (at any height) with the head pointing down, apparently so as to see better. In conclusion, the three species are strict sit-and-wait' visual hunters that are dependent on light.     

Prey choice and raiding behaviour of the Ponerine ant Pachycondyla analis (Hymenoptera: Formicidae)

Termite raiding behaviour of the African poneromorph ant Pachycondyla analis was studied at Mpala, Kenya. In all, 330 raids were observed with the raiding activity showing peaks in the morning and evening. Time spent at the termite source was positively correlated with the numbers of termites taken. The sizes of foraging parties, number of termites taken, distance travelled and time spent at termite sources also showed a positive correlation. Pachycondyla analis preyed significantly more on Microtermes spp. than they did on Odontotermes spp. but no significant differences were found in terms of predator efficiency even though many ants were injured in raids on Odontotermes spp. compared with those on Microtermes spp. Our results indicate that P. analis seems to forage optimally, balancing the costs of energy with prey reward and prey choices were not only influenced by prey abundance, but also by the costs of foraging, as influenced by prey defences, size and foraging behaviour.     

Foraging ecology and behaviour of the ponerine ant Ectatomma opaciventre Roger in a Brazilian savannah

This study provides a detailed account of the foraging behaviour of the ponerine ant Ectatomma opaciventre in a ‘cerrado’ savannah in south-east Brazil. Our observations suggest that this species has an exclusively diurnal foraging pattern. Feeding habits included both predation and scavenging, with termite workers and leaf-cutting ants as the most important food items. Contrary to all other Ectatomma species studied to date, no liquid food such as hemipteran honeydew or plant nectar was collected. Foragers showed clear individual foraging area fidelity.Workers of E. opaciventre employed a typical individual foraging strategy, i.e. there was no co-operation between foragers in the search for or retrieval of food, neither by tandem running nor by trail laying. Nest density was considerably lower than in other Ectatomma (0.015 nests per m²). The observed mean distance to the nearest neighbouring nest was 5.85 m, with a significant tendency toward over-dispersion. Nests were more frequently found in specific microhabitats, which may suggest active choice of nesting site by founding queens.     

Home range and foraging habitat selection by breeding lesser kestrels (Falco naumanni) in Greece

Home range size and foraging habitat use in breeding lesser kestrels (Falco naumanni), a bird species of conservation concern, were investigated during the breeding season of the species in 2008 in an intensively cultivated area of central Greece, using radio-tracking. Grasshopper (the main prey) densities were measured at the most important habitats (cotton, cereals, grasslands and margins). Home ranges were not significantly different between sexes either as overall means or during incubation and nestling periods. Movements of both sexes were non-random during incubation but random during the nestling period. Habitats used by males during incubation ranked as: margins > other > cotton > corn > cereals and during nestling period as: cereals > margins > grasslands > corn > cotton. Female habitat use greatly differed ranking as cereals > cotton > grasslands during incubation and as grassland > cotton > corn > cereals > margins during nestling period. Female habitat use seemed to be in disagreement with the conditions generally favouring prey availability, probably for reasons associated with low and uniform distribution of grasshopper densities over the habitats.     

Social facilitation and food partitioning in the queenless ant Dinoponera quadriceps (Hymenoptera: Formicidae)

Social facilitation occurs when an animal is more likely to behave in a certain way in response to other animals engaged in the same behaviour. For example, an individual returning to the nest with food stimulates other ants to leave and to forage. In the present study we demonstrate the existence of new facets in the colony organization of Dinoponera quadriceps: a positive feedback between the incoming food and the activation of new foragers, and the occurrence of incipient task partitioning during the food sharing. Lower-ranked workers located inside the nest process protein resources and higher-ranked workers handle smaller pieces and distribute them to the larvae. In conclusion, D. quadriceps has a decentralized pattern of task allocation with a double regulatory mechanism, which can be considered a sophisticated aspect of division of labour in ponerine ants.     

Haematozoans,mites and body condition in the oceanic island lizard Gallotia atlantica (Peters and Doria, 1882) (Reptilia: Lacertidae)

We studied relationships among blood haemogregarines (Apicomplexa), ectoparasitic mites (Ophyonissus; Acari: Trombiculidae) and an endemic lizard host (Gallotia atlantica, Lacertidae) on an oceanic islet (Alegranza, Canary Islands). We asked whether blood infection, mite load and body condition were related in lizard subpopulations at two contrasting habitats. Both haemogregarine prevalence (100%) and intensity of parasitism (>1) were strikingly higher than values found for congeneric lizards from the other Canary Islands. There were few differences between habitats in infection levels, suggesting low influence of habitat on parasite performance. Both mite prevalence and intensity were very high, though only prevalence differed between habitats (higher in the richest and climatically more sheltered site). Body condition in lizards did not differ significantly between habitats. We found no association among blood parasite load, mite infection and lizard body condition. Results are discussed in the context of parasite‐host relationships on small islands as compared to larger areas such as continents.     

Does nutritional status constrain adoption of more costly and less risky foraging behaviour in an Amazonian shelter-building spider?

Individual nutritional status may increase marginal foraging costs and potentially drive animal foraging strategies. Here, we investigated how it might affect foraging strategies of the shelter-building spider Hingstepeira folisecens (Hingston 1932) (Araneidae). This spider can catch prey using two strategies with different relative costs: ‘pulling’ (higher energy expenditure) and ‘pursuing’ (lower energy expenditure). We conducted experiments by offering prey at a fixed distance from the shelter entrance to investigate if spiders with lower nutritional status would exhibit riskier but less costly foraging behaviours more frequently than spiders with better status. The nutritional status did not affect the foraging behaviours adopted by H. folisecens. Additionally, the frequency of both foraging behaviours was similar. Therefore, our results did not provide any evidence that individual nutritional status is a factor driving the selection of foraging behaviours in H. folisecens. We suggest that the malnourished spiders should adopt additional strategies to compensate for the costs of pulling behaviour, especially when prey is far from the shelter. Furthermore, it is possible that other factors, like relative prey size in relation to web size, can help us to understand the threshold that determines when such individuals must adopt one of two possible behaviours.     

The diet of coral-reef Mitridae (Gastropoda) from Guam; with a review of other species of the family

The diets of 16 species of the gastropod family Mitridae from coral-reef habitats around the Pacific island of Guam were investigated by gut content analysis. All species examined were specialist feeders upon sipunculans, with considerable dietary overlap between coexisting species. A review of the diets of mitrids from other places, shows that a sipunculan diet is now known for a total of 26 species. The family is the most trophically specialized of the more speciose gastropod families.     

Exploitation of Cornucopina tuba (Bryozoa: Cheilostomata) by Aetea curta (Bryozoa: Cheilostomata)

Distal portions of zooids of uniserial, encrusting Aetea colonies curve abruptly away from the encrusted substratum. This characteristic, plus highly directional growth capability, enabled A. curta infesting an erect Cornucopina tuba colony to position its feeding structures consistently above the host colony, perhaps as a rheophilic growth response of individual zooids to feeding currents set up by the host.