Diet composition of the golden jackal (Canis aureus, L.) in Bulgaria, where the largest jackal population in Europe occurs, has been studied by scat analysis in a typical and newly occupied agricultural environment. The study was carried out during late summer and early autumn, a period when small mammal density is high. The food of the jackal typically consisted of small-sized and wild-living prey species. Rodents have been found to represent the primary food of the jackal (biomass estimation: 59.3 %, mainly Microtus spp.), and the European brown hare (Lepus europaeus, 20.1 %) and plants (19.7 %, mainly fruits) are secondary foods. Other prey, such as birds (mainly passerines), reptiles and invertebrates had been consumed in a low biomass ratio. No remains of wild ungulate and domestic animals have been detected in the studied scats.
The diet of fennec fox has been investigated for the first time from scats collected during one year in three localities of the north-eastern Algerian Sahara: Guemar and Sanderouce (near Oued Souf) and Bamendil (near Ouargla). In Guemar, 160 items in 20 scats were identified including 93 insects (58.1 %), 11 plant fragments (6.9 %) and 38 dates of Phoenix dactylifera (23.8 %). In terms of biomass, with 37.4 % plant material was the most abundant, followed by birds (29.9 %) and mammals (14.9 %). In Sanderouce, 491 items in 37 scats were identified including 377 insects (77.1 %), 10 plant fragments (2.0 %) and 29 dates (5.9 %). In terms of biomass mammals (56.6 %) were far more abundant than squamates (15.4 %) and vegetal food (12.8 %). In Bamendil, 1246 items in 57 scats were identified; insects were the most numerous (87.9 %) followed by mammals (only 3.7 %), however the biomass of mammals was the highest (63.5 %) followed by birds (19.8 %) and insects (5.5 %). As was suggested by behavioural records, the diet of the fennec fox was mainly carnivorous, but included a significant amount of vegetal items, particularly dates collected in oases.
The habitat choice of foraging bats depends on the local food supply as well as on vegetation structures that may enable the animals to orientate by echolocation. We examined the associations of bats with different types of landscape elements. Effects of the local insect occurrence, of the canopy structure and of linear vegetation elements on the presence of bats were compared. Bat activity increased with the insect abundance (p = 0.025). Furthermore, regression analysis revealed that bat activity was positively correlated (p = 0.004) with the relative area of open canopy type (clearances, still waters), and vise versa was negatively associated with the area of closed canopy (p = 0.0005). Bat species that predominantly forage in different vertical strata (above or below the canopy), differed in the activity at the various habitat types. Pipistrelle bats and Myotis species favoured open canopy areas (p = 0.007; p= 0.029), whereas Nyctalus species were not significantly more active at this patch type, compared to closed canopy areas (p = 0.0712). Linear characteristics of the vegetation (edges, paths) in general did not regulate the local preferences of bats (p = 0.154), but they corresponded to bat activity in complex structured areas (e.g. clearances with trees; p = 0.008).
Accurate Batesian mimicry is known to impose constraints on some traits of the mimic, such as foraging or reproductive behaviour. It is not known whether life-history traits of inaccurate Batesian mimics are constrained as well. We studied selected life-history traits of three spider species, Liophrurillus flavitarsis, Phrurolithus festivus (both Corinnidae), and Micaria sociabilis (Gnaphosidae), that are inaccurate mimics of ants. Namely, we were interested in how myrmecomorphy (ant-like resemblance) constrains their circadian activity, trophic niche and reproductive behaviour. The spiders were found to have diurnal activity like their models, whereas their close relatives have nocturnal activity. The three mimics do not catch ants, nor do they use food resources of ants, but catch various tiny invertebrates that occur in the vicinity of their models. Their trophic niche seems to be constrained by occurrence among ants. Absence of courtship and long lasting copulation, in a position that does not provide protective resemblance, do not seem to be constrained by mimicry in the three species. Comparative analysis of fecundity in mimetic and non-mimetic spiders showed that clutch size is also not constrained. Unlike in accurate mimics, life-history traits of inaccurate myrmecomorphs appear not to be constrained. and Stano Pekár, Martin Jarab.
Empirical protocols for assessing the suitability of prey for aphidophagous coccinellids are examined and a modified scheme of categorization is presented. It is argued that prey suitability should be assessed independently for larval development and adult reproduction because of potentially divergent nutritional requirements between these life stages. A scheme is proposed for assessing prey suitability for larval development using conspecific eggs as a reference diet against which diets of various prey types can be compared both within and among coccinellid species. Among suitable prey (those that support ca. 100% survival of larvae to the adult stage), those that promote faster development and yield larger adults relative to a conspecific egg diet are considered "optimal" for larvae. Prey that yield viable adults with similar or reduced adult weight after a similar or extended period of development relative to a diet of conspecific eggs are classified as "adequate". Prey are "marginal" if they support the survival of some larvae, but significantly less than 100%. Supplementary water should be provided with any non-aphid diet (e.g. pollen and alternative sources of animal protein) given the potential for food-specific diet-drought stress interactions. For adults, suitable prey are classified as "adequate" if they support the production of viable eggs when fed as a monotypic diet, or "marginal" if they merely prolong adult life relative to a water source. Prey that comprise an optimal or adequate diet for both larval development and adult reproduction are termed "complete" and these can be indexed for relative suitability according to derived estimates of rm. Potential sources of error in diet evaluation studies are identified and discussed.
Qualitative and quantitative differences in prey are known to affect the life histories of predators. A laboratory study was used to evaluate the suitability of three aphid prey, Aphis gossypii, Aphis craccivora and Lipaphis erysimi, for the ladybird beetle, Anegleis cardoni (Weise). Development was fastest on A. gossypii followed by A. craccivora and L. erysimi. Percentage pupation, immature survival, adult weight and the growth index were all highest when reared on A. gossypii and lowest on L. erysimi. Similarly, oviposition period, lifetime fecundity and egg viability were all highest on a diet of A. gossypii, lowest on L. erysimi and intermediate on A. craccivora. Age-specific fecundity functions were parabolic. Adult longevity, reproductive rate and intrinsic rate of increase were all highest on A. gossypii and lowest on L. erysimi. Life table parameters reflected the good performance on A. gossypii and poor performance on L. erysimi. Estimates of individual fitness values for the adults reared on A. gossypii and A. craccivora were similar and higher than that of adults reared on L. erysimi. Thus, the three species of aphid can all be considered essential prey for A. cardoni.
At a nest site in Northern Italy of females of the weevil-hunting digger wasp Cerceris arenaria L. (Hymenoptera: Crabronidae) the provisioning activity and predator-prey relationship were investigated, in particular their specialization in choice of prey. Females were active from middle of June to end of July, and from 8.00 to 19.00. The wasps made provisioning flights throughout the day, mostly in late morning and early afternoon. Individual wasps generally only hunted for 1 or 2 prey species of all those available, maybe because of their higher abundance. The size of prey, which is positively correlated with that of the female wasps, seems to be the main factor determining choice of prey. The nature of the provisioning flights seems to be related to the size of the prey, being more frequent and shorter for smaller weevils. The correlation between prey and wasp biomass is discussed in relation to the size range of the wasps.
Some features of the biology and feeding relationships of small waterbugs (Notonectidae, Corixidae, Pleidae, Helotrephidae, Aphelocheiridae) and ripicolous bugs (Gelastocoridae, Ochteridae) are reviewed. Individual families are discussed as predators or as prey of other animals. Special attention is given to characteristics and relationships that affect human beings directly or indirectly. The most important relationships from the economic point of view are: bugs and blood-sucking Diptera, bugs and fish, bugs and some endangered or protected amphibians and water birds. Of less importance is the occasional use of some aquatic bugs as saprobity bioindicators. It seems that the economic importance of these bugs has been underestimated.
Ten aphid species wcre used as prey for Adalia bipunctata and six of them (Euceraphis betulae, Cavariella konoi, Liosomaphis berberidis, Acyrthosiphon ignotum, Aphis farinosa and Macrosiphoniella artemisiae) are new essential preys for this coccinellid. Eucallipterus tiliae and E. betulae were the most suitable prey according to the rate of larval development, larval mortality, adult fresh weight and coccinellid abundance in the field. They are followed by L. berberidis, C. konoi and Tuberculatus annulatus. M. artemisiae and A. ignotum are also very profitable food in the laboratory, but they do not occur in the field together with A. bipunctata. A. farinosa from Salix caprea and Aphis fabae from Philadelphus coronarius were not very suitable as food due to the larval mortality (27% and 23%, respectively). A. fabae from Atriplex sagittata was an unsuitable prey: larval mortality was 67% and the adults that emerged as the survivors had the lowest weight recorded in this series of experiments. Aphis spiraephaga was also unsuitable prey: all 1st instar larvae of A. bipunctata died, even though slowly.
Data on the webs, prey spectrum, density and fecundity of Theridion impressum from three different habitats [fields of sunflower, fiddleneck (Phacelia), and apple trees] are presented and discussed. The volume of webs were found to vary between 5 (the first free instar) to 117 cm3 (subadult and adult specimens). The mean density of adult spiders per plant was 0.7 (sunflower), 1.5 (fiddleneck) and 1.2 (per apple branch). Spiders preferred to build webs in the upper part of vegetation or at the extremities of tree branches. The prey spectrum was assessed by collecting webs and identifying their contents. Prey items were primarily aphids (73%), Diptera (7.5%), acid Coleoptera and Hymenoptera (both 5.4%). Pests comprised 90% of the prey; the remaining 10% was accounted for by natural enemies, pollinators and other insects. The number of insects captured in webs differed among study habitats (sunflower > fiddleneck > apple tree) though this difference was not statistically significant. Due to greater numbers of aphids in webs on sunflower, the mean prey length was significantly smaller on sunflowers than in other plots. An index of fecundity was obtained by counting the number of eggs in eggsacs. This varied from 48 to 156 per eggsac and was not significantly different between study plots. The number of eggs was strongly correlated with numbers of prey captured per spider.