Using faecal metabarcoding to examine consumption of crop pests and beneficial arthropods in communities of generalist avian insectivores

Generalist insectivorous birds can provide ecosystem services in agricultural landscapes by consuming arthropod pests, or they can provide disservices when they consume beneficial arthropods. To examine bird impacts on arthropod communities, including pest control services, we need to know which arthropods birds commonly consume. Faecal metabarcoding is an emerging technique that can be used to identify prey from faecal samples, often to the species level. We used faecal metabarcoding to study diets of birds inhabiting the ecotone between soybean fields and adjacent grasslands in a largely agricultural landscape in Illinois, USA, during the summer of 2017. Whereas previous studies have used faecal metabarcoding to compare bird diets among species or among capture sites, we analysed samples from multiple species within a community at replicate sites. We collected and sequenced DNA from 132 faecal samples from 25 bird species captured at six sites. We found that birds consumed an extremely large and varied diet that differed among both species and sites, suggesting that birds were consuming prey opportunistically as available at each site. Of the nine most commonly detected prey species, three are known pests of soybeans. Bird diets also contained significantly more species of herbivorous prey than natural enemies. Finally, we discovered that American Goldfinches Spinus tristis, a highly granivorous species, may consume arthropods more frequently than expected and thus may provide ecosystem services in agricultural landscapes. Our study demonstrates that birds within this system consume a large variety of prey, suggesting that they may be able to respond quickly to pest outbreaks and contribute to agricultural resiliency.     

Feeding ecology of a vertebrate assemblage inhabiting a stream of NW Spain (Riobo; Ulla basin)

The food resource use of a stream in NW Spain by fish (Salmo trutta L. and Anguilla anguilla L.), birds (Cinclus cinclus L. and Motacilla cinerea L.) and mammals (Galemys pyrenaicus G. and Neomys anomalus C.) was studied. Data on seasonal diets and stream benthos prey were used to determine prey selection patterns.Caddisfly larvae are the main resource for Cinclus and Galemys, but these predators also consumed other benthic prey. Salmo fed on a wide range of benthic invertebrates, emergent pupae and terrestrial prey, whereas Anguilla consumed primarily benthic invertebrates, especially Lumbricids. Neomys fed mainly on terrestrial prey (Gasteropods and Lumbricids), but also consumed aquatic prey. Motacilla captured aquatic insects both in larval and aerial stages, as well as terrestrial prey.Both prey availability and selection led to seasonal differences in the use of food resources. All species showed a marked prey selection of aquatic taxa. Prey size plays an important role in this selection, most species consuming the largest of available prey sizes. In spite of the fact that all species feed upon freshwater invertebrates, substantial resource partitioning was observed in all seasons. This partitioning may be attributable to morpholological and physiological differences. Nevertheless, Anguilla and Galemys, two quite different animals, did feed on the same prey much of the time.     

Diet and prey profiles of three sympatric large carnivores in Bandipur Tiger Reserve, India

We conducted a field study of diets of three sympatric large carnivores, the tiger Panthera tigris , the leopard Panthera pardus and the dhole Cuon alpinus in Bandipur Tiger Reserve, India, based on analyses of 381, 111 and 181 scats, respectively. The frequency of occurrence of prey items in scats was converted to relative biomass and number of prey consumed using regression equations based on earlier feeding trials. The results showed that although these predators kill ∼11–15 species of vertebrate prey, relatively abundant ungulate species provide 88–97% of biomass consumed by them. Although the dietary niche overlap among the three species was high (Pianka's index of 0.75–0.93), some specialized predation was observed. The largest ungulates, gaur Bos gaurus and sambar Cervus unicolor , provided 73% of biomass consumed by tigers, whereas medium-sized chital Axis axis and wild pig Sus scrofa formed 65 and 83% of the biomass intake of leopards and dholes, respectively. In terms of the relative numbers of prey animals killed by the three predators, chital, which is the most abundant prey species, dominated their diets (tiger=33%, leopard=39% and dhole=73%). The results of the study, in conjunction with earlier work, support the prediction that abundance of ungulate prey species, as well as their availability in different size classes, are both critical factors that facilitate sympatry among the three predators.     

Prey‐mediated changes in the selectivity of the predator Macrolophus pygmaeus (Heteroptera: Miridae)

When foraging in communities with mixed prey, generalist predators may be confronted with prey species that differ in quality, size and mobility and interact with one another. To examine prey selection, predation by Macrolophus pygmaeus (Heteroptera: Miridae) was recorded by providing a diet of either one or two prey species of Myzus persicae (third‐instar nymphs), Aphis gossypii (fourth‐instar nymphs), Trialeurodes vaporariorum (third‐instar nymphs) and Ephestia kuehniella (eggs). In the experiments, prey mobility, prey quality and prey biomass were considered. The biomass consumed by the predator was dependent on the combination of prey species and the quantity of biomass offered. In choice experiments with diets mixed of two prey species at equal densities, the predation to A. gossypii was significantly reduced in the presence of E. kuehniella but the rate of consumption of M. persicae, T. vaporariorum and E.kuehniella was not significantly affected by the coexistence of any other species in the mixed prey diet. When equal amounts of biomass from two prey species were provided in combination, the total consumed biomass was significantly reduced in the mixed prey diets composed of E. kuehniella eggs and aphid nymphs. Thus, under the mixed‐prey situation, prey selection by predators may be affected by interactions among prey species differing in traits such as quality, mobility and size.     

Feeding Responses of Hatchery-Reared Gilthead Sea Bream (Sparus aurata L.) to a Commercial Diet and Natural Prey Items

Many fish species have evolved feeding mechanisms and behaviours enabling them to feed on specific prey. However, such mechanisms may not be optimal for feeding on commercial-pelleted diets in aquaculture. Gilthead sea bream chew and occasionally eject pellets or parts of pellets from the mouth when feeding on commercial diets. This may result in an increase in nutritional waste from the intensive culture of this species. In this study we examined the prevalence of this food processing behaviour in two sizes of sea bream, feeding on three types of natural prey items in comparison to a commercial pellet, to give an insight into the circumstances in which excess chewing and ejection of food items from the mouth occurred. These included two hard-textured food items (commercial pellet and hard-shelled prey) and two soft-textured food items (larvae and small crustacean). Both sizes of sea bream frequently consumed the soft-textured food types, however large sea bream also frequently consumed hard-textured pellets. Hard-textured food required longer handling times and elicited more chewing and the ejection of food items from the mouth. These results suggest that future investigations on the food processing behaviour and consequent waste when fed commercial diets differing in texture could give an insight into improving diets and feeding efficiency for intensively cultivated gilthead sea bream.     

Feeding Responses of Hatchery-Reared Gilthead Sea Bream (Sparus aurata L.) to a Commercial Diet and Natural Prey Items

Many fish species have evolved feeding mechanisms and behaviours enabling them to feed on specific prey. However, such mechanisms may not be optimal for feeding on commercial-pelleted diets in aquaculture. Gilthead sea bream chew and occasionally eject pellets or parts of pellets from the mouth when feeding on commercial diets. This may result in an increase in nutritional waste from the intensive culture of this species. In this study we examined the prevalence of this food processing behaviour in two sizes of sea bream, feeding on three types of natural prey items in comparison to a commercial pellet, to give an insight into the circumstances in which excess chewing and ejection of food items from the mouth occurred. These included two hard-textured food items (commercial pellet and hard-shelled prey) and two soft-textured food items (larvae and small crustacean). Both sizes of sea bream frequently consumed the soft-textured food types, however large sea bream also frequently consumed hard-textured pellets. Hard-textured food required longer handling times and elicited more chewing and the ejection of food items from the mouth. These results suggest that future investigations on the food processing behaviour and consequent waste when fed commercial diets differing in texture could give an insight into improving diets and feeding efficiency for intensively cultivated gilthead sea bream.     

Feeding habits and niche partitioning in a predator guild composed of tigers, leopards and dholes in a temperate ecosystem in central Bhutan

We describe the food habits, niche overlap and prey preferences in a predator guild comprised of tigers Panthera tigris , leopards Panthera pardus and dholes Cuon alpinus in a mountainous region of central Bhutan. Scat analyses revealed that these predators consumed 11 different prey species including livestock and rodents, of which leopards consumed 11. The combined relative occurrence of the three species, sambar Cervus unicolor , muntjac Munticus muntjac and wild pig Sus scrofa , constituted 42.7, 33.7 and 71.1% of the tiger, leopard and dhole diets, respectively, while livestock comprised 44.5, 73.4 and 15.9% of the prey consumed, respectively. Regression equations from earlier feeding trials were used to estimate the relative biomass and the numbers of prey consumed. Results showed that sambar featured more frequently than did muntjac and wild pig in the diets of tiger, leopard and dhole and contributed more relative biomass than did muntjac and wild pig. Sambar, muntjac and wild pig together provided 36.9, 28 and 63.1% of the biomass consumed by tigers, leopards and dholes respectively. All else being equal, there was evidence that all three predators ate livestock less than might have been expected on the basis of the abundance and high biomass of this prey category in the area. There was a high dietary niche overlap between the predators (Pianka's overlap index of 0.58–0.92), with a greater overlap between the two felid species than between the felids and the canid. This study provides evidence of a substantial diet overlap among the three sympatric carnivores, and thus highlights the potential for high intra-guild competition among them, especially given the relatively low density of prey.     

Naticid gastropod predation in the Gatun Formation (late Middle Miocene), Panama: preliminary assessment

Understanding predator-prey interactions is an important component of community studies, both present and past. Patterns of naticid predation in a fossil molluscan assemblage were studied by examination of drilling frequencies in a series of samples collected at three sites of the Gatun Formation (late Middle Miocene), Panama. Overall drilling intensities were relatively low (18 %) and were not correlated with abundance. Turritellids, turrids, and terebrids (making up to 11 % of the studied fauna) were the most consumed, representing almost 29 % of the total prey. Especially important were turritellids representing over 20 % of the total consumed prey. Albeit abundant (54 % of the studied fauna), columbellids, cerithiids, and marginellids showed low drilling intensities (8.2–10.4 %). Naticids were the major predators. Con-familial drilling among naticids is high and did not seem to be related to absence of preferred prey. Consistent with other studies, these data indicate that predators demonstrate high prey selectivity.     

Drivers of jaguar (Panthera onca) and puma (Puma concolor) predation on endangered primates within a transformed landscape in southern Mexico

Human pressures have increasingly placed keystone species, such as large cats, under threat. Together with forest loss, prey depletion is one of the main threats to the survival of jaguars (Panthera onca) and pumas (Puma concolor) throughout the Neotropics. Generally, primates are not considered main prey for jaguar and puma, and their inclusion in the diet could be indicative of ongoing prey species decline. Here, we investigate the effect of habitat type and disturbance on primate predation by large cats. Surveys took place during the dry seasons (March to June) of 2010 and 2011, covering a total of 608.5 km across 24 localities in the Uxpanapa Valley, Mexico. We found 65 felid scat samples with the aid of a wildlife scat detection dog, and then examined them to identify predator species and classify the prey remains they contained. Primates represented the most frequent prey (35%) for both jaguar and puma in our study site and constituted approximately half of the biomass consumed by these felines in the area. Primate remains were more likely to be found in scats surrounded by the lowest percentage of conserved forest or in areas surrounded by more villages, showing the potential effects of human activities on these species' populations. The high proportion of primates found in scats within our study site could be an early indication that populations of ungulates and other “typical” prey are beginning to collapse, and urgent conservation interventions are needed for both large cats and primates before they become locally extinct. Abstract in Spanish is available with online material.     

Diet of brown trout in relation to variation in abundance and size of pelagic fish prey

The seasonal diet of a predator, brown trout Salmo trutta [total length ( L _T) 17–69 cm] and simultaneous density and size‐structure of prey populations, vendace Coregonus albula and smelt Osmerus eperlanus (4–16 cm L _T), in a large boreal lake were analysed and compared in 2001 and 2002. The upper L _T limit for consumed prey was c . 40% of the predator L _T. All brown trout, however, preferred small (<10 cm L _T) and avoided large (≥10 cm L _T) prey. The results also suggested that equal densities of similar‐sized (4–10 cm L _T) fish of the two prey species led to random foraging on these species by brown trout, but if either one of the prey species predominated (>50%) in the lake, brown trout shifted to foraging on this species almost exclusively. Brown trout diets thus reflected the density dynamics of the two alternative prey species.     

Diets of Introduced Predators Using Stable Isotopes and Stomach Contents

ABSTRACT In a study of predation on ground-nesting birds at South San Francisco Bay (South Bay), California, USA, we analyzed stomach contents and stable isotopes of carbon and nitrogen to identify commonly consumed prey. We obtained the stomach contents from 206 nonnative red foxes (Vulpes vulpes regalis) collected in the South Bay area and Monterey County during 1995–2001 and from 68 feral cats (Felis silvestris) from the South Bay area during 2001–2002. We determined prey identity, biomass, and frequency, described seasonal diet trends, and derived an Index of Relative Importance. Avian species were the most frequent prey we found in the stomachs of red foxes from South Bay (61%), whereas small rodents were most frequent for red foxes from Monterey County (62%). Small rodents were the most frequent prey we found in feral cats (63%). Carbon and nitrogen isotopic signatures for foxes supported stomach content findings. However, isotope results indicated that cats received a majority of their energy from a source other than rodents and outside the natural system, which differed from the stomach content analysis. We demonstrated the utility of both stable isotope and stomach content analyses to establish a more complete understanding of predators' diets. This information aids natural resource managers in planning and evaluating future predator-removal programs and increases our understanding of the impacts of nonnative foxes and cats on native species.     

Proportion of prey consumed can be determined from faecal DNA using real-time PCR

Reconstructing the diets of pinnipeds by visually identifying prey remains recovered in faecal samples is challenging because of differences in digestion and passage rates of hard parts. Analysing the soft-matrix of faecal material using DNA-based techniques is an alternative means to identify prey species consumed, but published techniques are largely nonquantitative, which limits their usefulness for some applications. We further developed and validated a real-time PCR technique using species-specific mitochondrial DNA primers to quantify the proportion of prey in the diets of Steller sea lions (Eumetopias jubatus), a pinniped species thought to be facing significant diet related challenges in the North Pacific. We first demonstrated that the proportions of prey tissue DNA in mixtures of DNA isolated from four prey species could be estimated within a margin of ～ 12% of the percent in the mix. These prey species included herring Clupea palasii, eulachon Thaleichthyes pacificus, squid Loligo opalescens and rosethorn rockfish Sebastes helvomaculatus. We then applied real-time PCR to DNA extracted from faecal samples obtained from Steller sea lions in captivity that were fed 11 different combinations of herring, eulachon, squid and Pacific ocean perch rockfish (Sebastes alutus), ranging from 7% to 75% contributions per meal (by wet weight). The difference between the average percentage estimated by real-time PCR and the percentage of prey consumed was generally <12% for all diets fed. Our findings indicate that real-time PCR of faecal DNA can detect the approximate relative quantity of prey consumed for complex diets and prey species, including cephalopods and fish.     

Population dynamics and community analysis of the parasite fauna of juvenile spot, Leiostomus xanthurus (Lacepede), and Atlantic croaker, Micropogonias undulatus (Linnaeus), Sciaenidae) in two estuaries along the middle Atlantic coast of the United States

The parasite communities of juvenile spot, Leiostomus xanthurus Lacepede, and Atlantic croaker, Micropogonias undulatus (Linnaeus), changed with size, season. and geographical area. A total of 21 parasitic species occurred in juvenile spot and 19 occurred in juvenile croaker from Chesapeake Bay and Pamlico Sound. More parasitic species were acquired as juveniles grew, diversified their diets, and consumed larger numbers of intermediate hosts. They were also exposed to infective larvae of parasites with direct lifecycles over long periods of time. Equibility and, thus, diversity were depressed because of large numbers of Diplomonorchis /eiostomi Hopkins, I941 that dominated the parasite communities of both species. Although spot and croaker from both estuaries shared eight and six parasites, respectively, many of these non-specific parasites (generalists) were more common in both spot and croaker from one estuary than from the other. All species occurring in both hosts have indirect life cycles suggesting that the availability of certain intermediate hosts as prey was an important determinant of infection. Estuary of residence was clearly as important as host species identity in determining parasite community structure.     

Foraging ecology and niche overlap in pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales from waters of the U.S. mid‐Atlantic coast

A complementary approach of stomach content and stable isotope analyses was used to characterize the foraging ecology and evaluate niche overlap between pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales stranded on the U.S. mid‐Atlantic coast between 1998 and 2011. Food habits analysis demonstrated both species were primarily teuthophagous, with 35 species of cephalopods, and 2 species of mesopelagic fishes represented in their overall diets. Pianka's Index of niche overlap suggested high overlap between whale diets (O_n = 0.92), with squids from the families Histioteuthidae, Cranchidae, and Ommastrephidae serving as primary prey. Pygmy sperm whales consumed slightly larger prey sizes (mean mantle length [ML] = 10.8 cm) than dwarf sperm whales (mean ML = 7.8 cm). Mean prey sizes consumed by pygmy sperm whales increased with growth, but showed no trend in dwarf sperm whales. Significant differences were not detected in δ¹⁵N and δ¹³C values of muscle tissues from pygmy (10.8‰ ± 0.5‰, ?17.1‰ ± 0.6‰), and dwarf sperm whales (10.7‰ ± 0.5‰, ?17.0‰ ± 0.4‰), respectively. Isotopic niche widths also did not differ significantly and dietary overlap was high between the two species. Results suggest the feeding ecologies of the pygmy and dwarf sperm whales are similar and both species occupy equivalent trophic niches in the region.     

Primates are an important food resource for leopards (Panthera pardus) in Mahale,Tanzania

Leopard diets in the Kasoje area of the Mahale Mountains National Park, Tanzania, were analysed by inspecting prey remains in 256 scats. This area is unique as leopard density is high despite a relatively low density of medium-sized ungulates, regarded as the most preferred prey of leopards. At least eleven prey mammal species were confirmed in the scats. Small prey mammals up to 10 kg comprised 91.4% of the relative biomass consumed; the mean prey biomass in each scat was 7.6 kg. Blue duiker (31.2%) was the most dominant prey species, followed by the red colobus (29.2%), semi-terrestrial Cercopithecinae (the vervet monkey and yellow baboon combined) (10.5%) and the red-tailed monkey (9.9%). At the order level, the most consumed prey taxon was Primates (53.8%), followed by Cetartiodactyla (39.6%) and Rodentia (5.8%). Among primates, the blue monkey was the most preferred prey species, followed by the red colobus and semi-terrestrial Cercopithecinae. High consumption of primates is a unique characteristic of the leopards in Mahale. This trend exemplifies the flexibility of leopards in their choices of prey, and such flexibility may be one of the underlying reasons for leopards exhibiting the broadest global distribution among all wild felid species.     

Attack responses of the southern Australian whelk, Lepsiella vinosa (Lamarck, 1822) (Gastropoda: Muricidae), to novel bivalve prey: an experimental approach

In their native ranges, muricid gastropods feed on similar prey, often bivalves and barnacles, which they usually drill. Throughout its wide southern Australian distribution, the intertidal Lepsiella vinosa feeds on a range of prey from barnacles and littorinid gastropods in the southeast to mussels in the southwest. A number of muricids have been introduced throughout the world, either with oysters or in ship ballast water. In their new environments, they switch to native prey but their feeding responses to them have never been studied in the laboratory. The object of this study was to study the feeding of L. vinosa on a suite of non-native species. Australian Lepsiella vinosa was taken to Hong Kong, offered five different possible prey species and allowed to feed to satiation for many weeks. Replacement of consumed prey items by similar-sized conspecifics was undertaken until trends emerged. Lepsiella vinosa readily attacked thick- and thin-shelled bivalves from Hong Kong’s sandy beaches, Anomalocardia squamosa and Caecella chinensis, respectively, and from rocky shores, Septifer virgatus and Hormomya mutabilis, again respectively. It attacked them all, as it does its major prey item, Xenostrobus inconstans, in its native southwestern Australia, by either drilling or marginal probing with its proboscis. It also preferred intermediate sized prey (10–15 mm shell length), as with its natural prey. It quickly attacked the sandy shore species, and Hormomya mutabilis and Mytilopsis sallei, the latter two being closely similar in shell form and size to its natural prey X. inconstans. Hormomya mutabilis was the most favored prey, and was most similar in shell form and thickness to X. inconstans. This study therefore suggests that if introduced elsewhere, L. vinosa could radically affect intertidal community structure.     

Diet and prey selection of sympatric tropical skinks

Most skinks are opportunistic predators, taking available prey from the environment as it is encountered. Variation in their diet composition is thought to reflect differences in prey abundance in the environment. We studied diet composition and prey selection in a community of three sympatric skink species (genus Carlia) in northern Australia by comparing contents of skink stomachs with arthropod prey available in their habitat. Carlia were entirely carnivorous and fed on a range of arthropod prey. We found high overlap in diet and prey size among the three species and between the wet and dry seasons, but found that skinks generally focused their foraging efforts on prey types and prey sizes that were not abundant in the habitat. Spiders (Aranea), orthopterans, blattarians, isopods and termites (Isoptera) were important prey of skinks, but these arthropods were rarely trapped in the environment. Skinks also frequently consumed large‐bodied prey, despite the higher relative abundance of small prey in the environment. Skinks were more selective in their foraging and diet than previously assumed. Selection of prey by consumers is a fundamental ecological process, important to consumers for maintaining energy requirements to grow and reproduce, but equally important to the community dynamics of the prey consumed.     

Predation of insects by feral cats (<Emphasis Type="Italic">Felis silvestris catus</Emphasis> L., 1758) on an oceanic island (La Palma,Canary Island)

Predation of insects by feral cats (Felis silvestris catus) on a heterogeneous oceanic island (La Palma, Canary Islands) was studied. A total of 127 invertebrates were identified in the analysis of 500 scats (100 from each habitat of the Island). Invertebrates appear in 18.00% of the scats, representing an insignificant percentage of the total consumed biomass by feral cats on La Palma Island (0.05%). Insects were the most common invertebrate prey both in percentage of occurrence (90.6%) and invertebrate biomass (93.53%), with a total of 115 prey items. Orthoptera, Lepidoptera and Coleoptera were the main prey groups. Among the five main habitats present in La Palma Island, the temperate forest shows the lowest consumption of invertebrates, although insect consumption did not show statistical differences. However Orthoptera and Lepidoptera were more frequently preyed on in the pine forest and in the xerophytic shrub, respectively. Moreover, applying the Simplified Morisita index, a different insect composition of the diet was observed among habitats. Although, none of insects predated by feral cats are threatened, the identification of invertebrate component of the feral cats’ diet is an important tool for the correct understanding of predation significance and to prevent damage to endangered insect species.     

Differences in diet and trophic interactions of Patagonian carnivores between areas with mostly native or exotic prey

The prey base for Patagonian carnivores has been altered greatly over the past 150 years due to widespread overgrazing by livestock, invasions by exotic wildlife, and hunting. On ranches in northern Patagonia carnivores consume mostly exotic species, and native herbivores are ecologically extinct in their role as prey. In this study we compare diets of the culpeo (Lycalopex culpaeus), chilla (L. griseus), puma (Puma concolor), Geoffroy's cat (Leopardus geoffroyi), colocolo (L. colocolo), and hog-nosed skunks (Conepatus chinga and C. humboldtii) in a reserve with a mostly native prey base to their diets on the ranches, and evaluate how differences in prey bases affect trophic interactions among carnivores. Carnivores in the reserve consumed mostly native prey. Dietary overlap among carnivores was not significant on the reserve, but was highly significant on the ranches. This homogenization of diets where densities of native species are reduced could lead to stronger negative interactions among carnivores, altering the composition of the carnivore assemblage to the detriment of the more specialized species. Study of carnivore diets may be a relatively quick way to evaluate the conservation status and ecological functionality of prey assemblages in Patagonia and other areas where these have been altered.     

Aversive Learning in the Praying Mantis (<Emphasis Type="Italic">Tenodera aridifolia</Emphasis>), a Sit and Wait Predator

Animals learn to associate sensory cues with the palatability of food in order to avoid bitterness in food (a common sign of toxicity). Associations are important for active foraging predators to avoid unpalatable prey and to invest energy in searching for palatable prey only. However, it has been suggested that sit-and-wait predators might rely on the opportunity that palatable prey approach them by chance: the most efficient strategy could be to catch every available prey and then decide whether to ingest them or not. In the present study, we investigated avoidance learning in a sit-and-wait predator, the praying mantis (Tenodera aridifolia). To examine the effects of conspicuousness and novelty of prey on avoidance learning, we used three different prey species: mealworms (novel prey), honeybees (novel prey with conspicuous signals) and crickets (familiar prey). We sequentially presented the prey species in pairs and made one of them artificially bitter. In the absence of bitterness, the mantises consumed bees and crickets more frequently than mealworms. When the prey were made bitter, the mantises still continued to attack bitter crickets as expected. However, they reduced their attacks on bitter mealworms more than on bitter bees. This contrasts with the fact that conspicuous signals (e.g. coloration in bees) facilitate avoidance learning in active foraging predators. Surprisingly, we found that the bitter bees were totally rejected after an attack whereas bitter mealworms were partially eaten (~35%). Our results highlight the fact that the mantises might maintain a selection pressure on bees, and perhaps on aposematic species in general.