Heterospecific Eggs Research Articles

Behavioural profiles in a wild population of a cooperatively breeding cichlid

AbstractIn cooperatively breeding species, subordinates can obtain group membership through social interactions with other group members or by providing services such as helping with territory defence. Large subordinate individuals, which can reproduce, are expected to adjust their behaviour as a function of the demand of help and group size because if the environmental conditions allow, they may either leave the group to start breeding or queue for the breeding position in their natal group. The number of helpers in a group is expected to affect the need of help by dominants and consequently also the level of subordination shown by helpers. In a series of field experiments, we manipulated the need of help and the opportunities for subordinates to show submissive behaviour in a wild population of the cooperatively breeding species Neolamprologus pulcher. We assessed if group size determines the social behavioural strategy of large subordinate individuals. When experimentally eliciting submissive behaviour, large subordinates from small groups showed a lower frequency of submissive behaviour compared to large groups; moreover, they tended to show a higher frequency of sand digging than in large groups. In contrast, neither territory defence in the presence of a heterospecific egg and larvae predator nor dispersal propensity, measured as prospecting frequency in neighbouring territories, was affected by group size. A principal component analysis revealed that prospecting is uncorrelated with submissive behaviour and helping behaviour. Our results suggest that group size may be involved in shaping behavioural phenotypes of juvenile subordinates.

Effects of co-occurrence and intra- and interspecific interactions between Drosophila suzukii and Zaprionus indianus.

In drosophilids, competition and coexistence can impact survivorship, growth, and reproductive output. Here, we evaluated direct competition between two co-occurring fruit flies, the spotted-wing drosophila Drosophila suzukii and the African fig fly Zaprionus indianus, comparing results from field collections with laboratory experiments. Field collections were conducted to evaluate co-occurrence between species. In the laboratory, different densities of eggs of each species were provided an artificial diet, and intra- and interspecific densities were evaluated regarding biological traits such as development and fecundity. Field collections showed a prevalence of Z. indianus, followed by other drosophilid species, including D. suzukii. Pupal survival and adult emergence were higher in D. suzukii than in Z. indianus at both intra- and interspecific densities, with decreasing values in response to increased densities. Fecundity did not differ significantly for either species at different intraspecific densities, but when reared together at different densities, Z. indianus was significantly more fecund than D. suzukii. Development time showed no significant difference at intraspecific densities, but when reared together, Z. indianus had longer development times than D. suzukii. Leslie Matrix projections indicated that D. suzukii showed practically the same dynamics at intraspecific and interspecific densities, with increasing oscillations at low and intermediate densities and decreasing oscillations at high densities. Zaprionus indianus showed a similar oscillation to D. suzukii, except at intermediate intraspecific densities, when the pattern was cyclic. Low interspecific densities resulted in decreasing oscillations. In the two-choice oviposition bioassays, D. suzukii females showed no significant preference for diets previously infested or not with either conspecific or heterospecific eggs at different densities. Understanding competitive interactions between co-occurring heterospecific species should be considered when establishing management tactics for spotted-wing drosophila.

Energy expenditure affects the larval food preference in Propylea dissecta (Coleoptera: Coccinellidae)

Abstract Food preferences and choices are common among animals, including insects. Studies on food preferences have been done on coccinellids using eggs and aphids as diet, but information on the food choices of the aphidophagous ladybird, Propylea dissecta (Coleoptera: Coccinellidae), under laboratory conditions, is scarce. This study examined the effect of physical activity (walking) on food choice. We reared P. dissecta larvae on aphids, Aphis craccivora (Hemiptera: Aphididae), until the fourth-instar stage, and then allowed the fourth-instar larvae to walk on a glass rod for different time intervals to illustrate the energetic costs of foraging. After walking, larvae were provided simultaneous food choices of equidistantly placed food, i.e., A. craccivora, conspecific eggs, and heterospecific eggs. As the walking time duration gradually increased, the level of larval activity increased, resulting in poorer food choices.

Changes in the gut microbial community of larvae of the harlequin lady beetle in response to cannibalism and intraguild predation

Diet affects the gut microbial community in most organisms, but the potential effects of cannibalism and intraguild predation (IGP) on the gut microbiota of predatory arthropods remain unexplored. Here, a series of feeding experiments examined changes in the gut microbial community of larvae of the predatory lady beetle Harmonia axyridis resulting from egg and larval cannibalism and IGP. We found that gut microbial abundance increased in fourth instar H. axyridis larva when conspecific eggs plus aphids were consumed as neonates, but did not change when their consumption was sustained across larval stages. In contrast, the consumption of Coccinella septempunctata eggs plus aphids over all larval stages decreased gut microbial abundance, whereas neonate consumption of the same had no such effect. Gut microbial composition differed following consumption of either conspecific or heterospecific eggs. Consumption of a C. septempunctata larva by molting H. axyridis third instar larvae decreased gut microbial abundance and diversity, whereas consumption of a conspecific larva increased them. Larval cannibalism and IGP appear to have variable effects on microbial composition due to differences in relative abundance of prevailing bacterial groups associated with these prey items. Our results indicate that cannibalism and IGP can have both quantitative and qualitative consequences for the gut microbial community in aphidophagous lady beetles.

Conflict over fertilization underlies the transient evolution of reinforcement.

When two species meet in secondary contact, the production of low fitness hybrids may be prevented by the adaptive evolution of increased prezygotic isolation, a process known as reinforcement. Theoretical challenges to the evolution of reinforcement are generally cast as a coordination problem, i.e., “how can statistical associations between traits and preferences be maintained in the face of recombination?” However, the evolution of reinforcement also poses a potential conflict between mates. For example, the opportunity costs to hybridization may differ between the sexes or species. This is particularly likely for reinforcement based on postmating prezygotic (PMPZ) incompatibilities, as the ability to fertilize both conspecific and heterospecific eggs is beneficial to male gametes, but heterospecific mating may incur a cost for female gametes. We develop a population genetic model of interspecific conflict over reinforcement inspired by “gametophytic factors”, which act as PMPZ barriers among Zea mays subspecies. We demonstrate that this conflict results in the transient evolution of reinforcement—after females adaptively evolve to reject gametes lacking a signal common in conspecific gametes, this gamete signal adaptively introgresses into the other population. Ultimately, the male gamete signal fixes in both species, and isolation returns to pre-reinforcement levels. We interpret geographic patterns of isolation among Z. mays subspecies considering these findings and suggest when and how this conflict can be resolved. Our results suggest that sexual conflict over fertilization may pose an understudied obstacle to the evolution of reinforcement.

Impact of egg-quality and its laying pattern on the fate of egg-cannibalism and intraguild predation in ladybirds

We investigated the impact of egg-quality and its laying pattern on the incidence of cannibalism and intraguild predation in ladybirds. We manipulated quality by using two species of ladybirds’ eggs and the pattern of egg-laying by arranging the eggs singly or in cluster and using second, third and fourth instar larva of two ladybird species, Coccinella septempunctata L. and Menochilus sexmaculatus (Fabricius), as predators. We found that second instars of both ladybird species indulged in egg-cannibalism, whereas third and fourth instars were potential intraguild predators and consumed heterospecific eggs. On the other hand, linearly arranged and clustered eggs of M. sexmaculatus were least protected by higher instars of C. septempunctata, while clustered eggs of C. septempunctata got a refuge from M. sexmaculatus higher stage larvae due to aposematism in eggs. It is concluded that C. septempunctata was an intraguild predator of eggs of M. sexmaculatus in starved conditions, and the egg-quality and pattern of egg-laying can affect the fate of egg-cannibalism and intraguild predation.

Food preference, growth and development of three aphidophagous ladybirds preying on conspecific and heterospecific eggs

Food preference, growth and development of three aphidophagous ladybirds preying on conspecific and heterospecific eggs

Effect of dietary history on intraguild predation and cannibalism of ladybirds’ eggs

Dietary history during immature development has a major influence on the evolution of food choices of aphidophagous ladybirds. We designed laboratory experiments to investigate the influence of consuming conspecific eggs or heterospecific eggs as the only food during larval development on the food choice of adult aphidophagous ladybirds, viz. Propylea dissecta (Mulsant) [Pd], Coccinella septempunctata L. [C7] and Menochilus sexmaculatus (Fabricius) [Ms]. We provided conspecific eggs and heterospecific eggs in presence of fewer aphids, Aphis craccivora (Koch) for 24-h to the adult males of the three ladybird species that were previously reared on monotypic conspecific or heterospecific egg-diet to determine their food choice. All ladybirds preferably consume aphids. However, amongst different egg-diets, mostly ladybirds prefer to feed on the same egg-diet, which they had consumed during the larval stage. Contrarily, C7 raised on conspecific eggs preferred different egg-diet (Pd eggs) than the same one. Furthermore, C7 reared on heterospecific eggs consumed these eggs more readily during adulthood than the conspecific eggs. This explains why C7 dominates coccinellid fauna, as an invader and an intraguild predator, in various geographical habitats. We concluded that prolonged exposure to unnatural diets, such as coccinellids’ eggs during immature development, tend to develop a craving for such diets during adulthood of ladybirds.

Kin recognition by the adults of a biological control agent, Propylea dissecta (Coleoptera: Coccinellidae)

The ability to recognize kin is a well-established behavior across several animal phyla including insects. A laboratory experiment was designed to find out whether adults of an aphid-biocontrol agent, Propylea dissecta (Coleoptera: Coccinellidae) may avoid consuming their own eggs in prey scarcity in the presence of unrelated conspecific eggs. For the purpose, starved parent ladybirds were provided with their eggs and unrelated conspecific (alien) eggs in the absence of their natural prey (aphids). The predatory/avoidance behavior of the parents towards alien-eggs and their eggs was recorded. The adult male of P. dissecta had lesser food demand than the female and consumed significantly lesser (0.7±0.20) kin eggs than the alien eggs (2.8±1.89). Similarly, the adult female cannibalized significantly lesser number of kin eggs (1.6±0.209) than the alien-eggs (3.5±0.15). Seemingly, both the parents had recognized their eggs and refrained from consuming them. This could be a strategy adopted by the parents to conserve their gene-pool and to further protect it by consuming the heterospecific eggs of potential enemies (alien eggs) in prey scarcity. This insurance of their gene-pool could benefit these parents by conserving their genetic lines.

Egg discrimination is mediated by individual differences in queen olfactory responsiveness and boldness

AbstractNest parasites attempt to shift the cost of rearing young from themselves to others. Despite strong selection to avoid this exploitation, there is considerable variation among-individuals in susceptibility to nest parasites. We evaluated the effects of individual variation in boldness, aggressiveness, and olfactory responsiveness on egg discrimination in wasps: Polistes metricus, which founds nests as singleton individuals, and P. dominula, which founds nests in small coalitions. Aggressiveness and boldness were evaluated using individuals’ response to mechanical disturbance, and olfactory responsiveness was evaluated using individuals’ tendency to respond to a novel rewarding stimulus. Egg discrimination was evaluated by presenting each queen with a variety of foreign eggs: 1) unaltered eggs laid by the resident (negative control group), 2) eggs produced by the resident female that were removed and replaced (procedural control), 3) eggs of foreign conspecifics (conspecific egg), and 4) eggs of a heterospecific congener (heterospecific egg). Females of both species never rejected untampered eggs and rejected procedural controls in only 35% of cases. Both species were twice as likely (70% rejection rate) to reject eggs of foreign conspecifics or heterospecifics. In P. dominula, bolder individuals and those with low olfactory responsiveness were more likely to reject foreign eggs. In P. metricus, boldness was not associated with egg rejection, but individuals with heightened olfactory responsiveness were more likely to reject foreign eggs. Thus, there are contrasting associations between behavioral phenotypes and egg rejection across species. These results are discussed in light of differences in the colony founding behavior of these species.

Intraguild predation between two aphidophagous coccinellids, Hippodamia variegata (G.) and Coccinella septempunctata L. (Coleoptera: Coccinellidae): the role of prey abundance

Intraguild predation (IGP) is a common phenomenon among the predacious coccinellids which involves a combination of predation and competition. The aphidophagous predators, Coccinella septempunctata L. and Hippodamia variegata (G.) comprise major part of coccinellid predator species in the agroecosystem of Turkey. We investigated the IG interactions between these aphidophagous predators under laboratory conditions. Our results revealed that predation of the eggs of H. variegata by the adult male, female and 4th instar larvae of C. septempunctata was maximum at 0 prey abundance, however, substantial number of eggs were also consumed at aphid densities of 30 and 80. Consumption of 1st and 2nd instar larvae was also higher in the absence of aphids, intermediate at 80 aphid density and greatly reduced or almost negligible at 350 prey abundance. The same sequence was also true for the predation of the different juvenile stages of C. septempunctata by H. variegata adult male, female and 4th instar larvae. The adult female and 4th instar larvae of both C. septempunctata and H. variegata proved to be more voracious towards different heterospecific juvenile stages compared to adult male. Results on the preference of C. septempunctata and H. variegata towards conspecific or heterospecific eggs revealed that both the aphidophagous coccinellids showed higher degree of preference for egg cannibalism (conspecific egg consumption) over IGP (heterospecific egg consumption).

Effect of territory intruders on the perceived quality of territorial males in an endangered pupfish, Cyprinodon bovinus

Abstract Social eavesdropping can guide mate choice and the assessment of competitor quality. In the endangered Leon Springs pupfish (Cyprinodon bovinus), males establish breeding territories that they defend from conspecifics and heterospecific egg predators. Females enter the breeding area to assess males and spawn in their territories. It was hypothesized that male and female C. bovinus eavesdrop on social interactions within male territories to evaluate each territorial male’s ability to exclude intruders and attract potential mates. Using a repeated design, a bottle containing either a female C. bovinus, a non-territorial male C. bovinus, a swarm of G. nobilis, or water was placed at the centre of a male’s territory. Territorial males received more spawns and females spawned more frequently per visit when a female stimulus was present. These results suggest that females eavesdrop to inform their mating decisions, but this may be limited to the assessment of extra-pair females within territories.

Effect of prey and pollen on interactions between Typhlodromus bagdasarjani and Phytoseiulus persimilis (Acari: Phytoseiidae) on cucumber (Cucurbitaceae)

AbstractIntraguild predation is a notable factor to proper application of biocontrol agents to reduce pest populations. Intraguild predation was studied between Typhlodromus bagdasarjani Wainstein and Arutunjan (Acari: Phytoseiidae) and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) in presence and absence of Tetranychus urticae Koch (Acari: Tetranychidae) as well as pollen. Intraguild predation between two predators was bidirectional. The highest and the lowest predation rates of both predators in absence and presence of T. urticae as well as in the pollen treatments were on heterospecific eggs and deutonymphs, respectively. Typhlodromus bagdasarjani consumed more heterospecific eggs compared with P. persimilis. When pollen was added, predation of T. bagdasarjani significantly reduced on heterospecific eggs and deutonymphs in absence and presence of T. urticae treatments, respectively. However, predation rate of P. persimilis on heterospecific stages was not significantly affected by pollen addition. Oviposition of both predators was higher in presence of T. urticae than in its absence and oviposition of P. persimilis was significantly higher on heterospecific stages than T. bagdasarjani. Pollen addition had a significant effect on increasing the oviposition rate of T. bagdasarjani. Extraguild prey presence had a nonsignificant effect on the consumption rate of intraguild prey by the intraguild predators. However, presence of extraguild prey led to a significant increase in oviposition rate of both predators.

Interkingdom Cues by Bacteria Associated with Conspecific and Heterospecific Eggs ofCochliomyia macellariaandChrysomya rufifacies(Diptera: Calliphoridae) Potentially Govern Succession on Carrion

Deciphering mechanisms that regulate succession on ephemeral resources is critical for elucidating food web dynamics and nutrient recycling. Blow fly (Diptera: Calliphoridae) colonization and utilization of vertebrate carrion serve as a model for such studies, as they are the primary invertebrates that recycle this ephemeral resource. Initial colonization by blow flies often results in heightened attraction and colonization by competing conspecifics and heterospecifics, thereby regulating associated arthropod succession patterns. We examined the response of Cochliomyia macellaria (F.) and Chrysomya rufifacies (Macquart) to conspecific and heterospecific eggs. Because Ch. rufifacies is facultatively predacious and cannabalistic, we hypothesized that adults would recognize the presence of conspecific and heterospecific eggs, thus avoiding potential predation and competition. Using a Y-tube olfactometer, we measured the residence time response of C. macellaria and Ch. rufifacies to conspecific and heterospecific eggs of three different age classes (fresh to 9-h-old). Fly responses to surface-sterilized eggs and to an aqueous solution containing egg-associated microbes were then examined. High-throughput sequencing was used to survey egg-associated bacteria from both species. We report that C. macellaria and Ch. rufifacies exhibit differential responses to eggs of conspecifics and heterospecifics, which appear to be a result of microbial volatile-related odors. These behaviors likely influence predator–prey interactions between species. Preliminary high-throughput sequencing revealed Ch. rufifacies had a similar egg-associated fauna as C. macellaria, which may serve as a form of camouflage, allowing it to colonize and thereby attract C. macellaria, a common prey for its larvae.

Heterospecific Infanticidal Behavior by Southern House Wrens (Troglodytes aedon musculus) Suggests Nest Site Competition

ABSTRACT Destruction of conspecific and heterospecific eggs and nestlings occurs in several species of passerines. Two main hypotheses have been proposed to explain the adaptiveness of this behavior: as a mechanism to avoid competition or to gain access to reproductive opportunities. In Colombia, Southern House Wrens (Troglodytes aedon musculus) broke eggs and/or killed nestlings of Spectacled Parrotlets (Forpus conspicillatus, 24 cases), Apical Flycatcher (Myiarchis apicalis, one case) and of other House Wrens (four cases). Wrens attacked parrotlet nests in three contexts: 1) wrens took over and used a parrotlet nestbox within their territory, 2) wrens with an active nest attacked a neighboring parrotlet nest, or 3) the attacker was unknown but was inferred to be a wren. Wrens also attacked trial nests with natural and artificial wren eggs that were placed near active wren nests. These observations suggest that infanticidal behavior by wrens at this locality may be driven by competition for nest sites. I...

Predatory behaviour of alpine (Ichthyosaura alpestris) and smooth (Lissotriton vulgaris) newts towards conspecific and heterospecific eggs and larvae

Consumption of conspecific and heterospecific eggs and larvae is common in many animal taxa, including many amphibians. Adult newts (Amphibia Urodela) often co-occur temporally and spatially with conspecific and heterospecific newt eggs and larvae, and adult individuals may benefit from their consumption, but little is known on the degree of discrimination in the newts’ predatory behaviour towards them. We performed two laboratory experiments to examine whether adult male and female alpine, Ichthyosaura alpestris (Laurenti 1768), and smooth, Lissotriton vulgaris (Linnaeus 1758), newts discriminate between conspecific and heterospecific eggs and larvae in their predatory behaviour. In our study, eight out of 64 newts succeeded in consuming eggs, although 3 times as many attacked them. We found no differences in predatory behaviour towards conspecific and heterospecific eggs, or between males and females in either species. Similarly, we found no evidence for the occurrence of discriminative predatory behaviour towards conspecific and heterospecific larvae. In our experiments the criterion for whether a newt would consume a prey item (egg or larva) was not the prey’s identity (species), but the newts’ ability to detect, capture and/or ingest it. Our results suggest that newts of both species follow an opportunistic foraging strategy, consuming whatever prey of appropriate size they manage to capture.

Egg rejection in blackbirds Turdus merula: a by-product of conspecific parasitism or successful resistance against interspecific brood parasites?

BackgroundTraditional theory assumes that egg recognition and rejection abilities arise as a response against interspecific brood parasitism (IBP). However, rejection also appears in some species that are currently not exploited by interspecific parasites, such as Turdus thrushes. Recent evidences suggest that rejection abilities evolved in these species as a response to conspecific brood parasitism (CBP). To test these two alternative hypotheses, we performed an experimental study by parasitizing nests of the common blackbird (Turdus merula) with conspecifics or heterospecific eggs under different risk of parasitism (presence of interspecific or conspecific parasites near the nest). Common blackbird is a potential host of the common cuckoo (Cuculus canorus) but suffers low levels of CBP too.ResultsWe found that blackbirds were able to recognize and eject heterospecific eggs at high rates whereas most of conspecifics eggs were not recognized and, therefore, accepted. Ejection rates of conspecific eggs did not exceed 13 %, even in situations of high risk of CBP (blackbird female placed near the nest), which contradict the main prediction derived from the CBP hypothesis. Conversely, ejection rates of experimental eggs simulating IBP were much higher (80–100 %). Furthermore, female blackbirds were more aggressive towards cuckoos than towards blackbird dummies.ConclusionsOur results considered together support the IBP hypothesis, indicating that recognition and rejection of parasitic eggs in blackbirds have probably evolved due to previous cuckoo parasitism. The current absence of IBP in blackbirds may be due to the highly efficient rejection abilities in this species. Thus, these abilities have been retained in absence of brood parasitism as a consequence of the low costs involved for blackbirds, resulting in a successful resistance against interspecific brood parasitism.

Egg Predation by the Introduced Lady Beetle, Coccinella septempunctata (Coleoptera: Coccinellidae), Lowers Mortality but Raises Relative Risk for the Native Lady Beetle, Coccinella novemnotata.

Populations of the native ninespotted lady beetle, Coccinella novemnotata Herbst, have undergone precipitous declines in North America following the establishment of the exotic sevenspotted lady beetle, Coccinella septempunctata L. Recent volunteer efforts have made it possible to establish colonies of the now-rare C. novemnotata and test mechanisms contributing to its decline. We evaluated the relative frequencies of intraguild predation and cannibalism of eggs between these two species. A single C. novemnotata or C. septempunctata adult was exposed to conspecific and heterospecific eggs in either the presence or absence of pea aphids. The study revealed two expected results: 1) eggs of C. novemnotata were consumed more frequently than eggs of C. septempunctata by both species, and 2) egg consumption was higher when aphids were absent, independent of predator and egg species. There were also two unexpected results from the study: 1) the asymmetry between egg predation rates was higher when aphids were present, and 2) higher predation rates on C. novemnotata eggs in the absence of alternate prey was due to a relatively higher rate of intraspecific cannibalism. This implies that C. novemnotata would have suffered higher egg mortality rates before the invasion of C. septempunctata, but even though the aggregate rate of egg predation on C. novemnotata eggs is lower post-invasion, it is still significantly higher than the aggregate rate of predation of C. septempunctata eggs. This differential pattern of asymmetric predation could contribute to habitat compression and the overall decline of C. novemnotata.

Can the predatory mites Amblyseius swirskii and Amblyseius eharai reproduce by feeding solely upon conspecific or heterospecific eggs (Acari: Phytoseiidae)?

The phytoseiid mite, Amblyseius swirskii (Athias-Henriot) is an exotic biological control agent of mites and small insect pests in China. Amblyseius eharai (Amitai & Swirski), on the other hand, is a native predacious mite common throughout East and South-East Asia and considered to be an important natural enemy of Panonychus citri (McGregor). Understanding the ways introduced predators affect native ones is vital if we wish to use the former as biological control agents in the field. In order to evaluate the interactions between these two predacious mites, we observed their life histories when they cannibalized or fed upon intraguild prey under laboratory conditions. Both male and female A. eharai and A. swirskii could develop to adulthood by feeding upon both conspecific and heterospecific (IGP) eggs. However, A. swirskii females supplied with IGP eggs had shorter developmental durations, higher fecundity, and higher intrinsic rates of increase (rm) than those supplied with conspecific eggs. On the other hand, A. eharai females supplied with conspecific eggs had higher rm than those supplied with heterospecific eggs, suggesting that A. eharai females may prefer to prey upon conspecific immatures, even when A. swirskii immature stages are present. As a result, A. swirskii females may decrease A. eharai populations, when extra-guild prey species, such as spider mites, and pollen are scarce.

Nest destruction elicits indiscriminate con- versus heterospecific brood parasitism in a captive bird.

Following nest destruction, the laying of physiologically committed eggs (eggs that are ovulated, yolked, and making their way through the oviduct) in the nests of other birds is considered a viable pathway for the evolution of obligate interspecific brood parasitism. While intraspecific brood parasitism in response to nest predation has been experimentally demonstrated, this pathway has yet to be evaluated in an interspecific context. We studied patterns of egg laying following experimental nest destruction in captive zebra finches, Taeniopygia guttata, a frequent intraspecific brood parasite. We found that zebra finches laid physiologically committed eggs indiscriminately between nests containing conspecific eggs and nests containing heterospecific eggs (of Bengalese finches, Lonchura striata vars. domestica), despite the con- and heterospecific eggs differing in both size and coloration. This is the first experimental evidence that nest destruction may provide a pathway for the evolution of interspecific brood parasitism in birds.