Do Development and Diet Determine the Degree of Cannibalism in Insects? To Eat or Not to Eat Conspecifics (original) (raw)
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Cannibalism in Two Subtropical Lady Beetles.pdf
Cannibalism is an important factor influencing both immature survival and adult reproductive success in aphidophagous lady beetles. This study employed three series of laboratory experiments to characterize life stage-specific cannibalism responses of Coccinella undecimpunctata L. and Cydonia vicina nilotica Mulsant to 1) different conspecific densities, with and without prey, 2) other life stages, and 3) various densities of prey, Myzus persicae Sulzer. All larval instars of both species cannibalized more in the absence of prey than in its presence at all conspecific densities, but in general, cannibalism increased with conspecific density only in the absence of prey, and more strongly for third and fourth instar C. undecimpunctata than for their C. vicina nilotica counterparts. Adults contributed the most cannibalism of any life stage, and eggs were the most vulnerable. In addition to cannibalizing their own and earlier instars, second and third instar C. undecimpunctata sometimes cannibalized third and fourth instars, respectively, and fourth instars occasionally ate pupae. Larvae of C. vicina nilotica were only preyed upon by the same or later stages and pupae, by adults, not fourth instars. A relative vulnerability index was calculated for each life stage based on its net vulnerability to cannibalism by all life stages and plotting these indices revealed species-specific patterns of diminishing vulnerability to cannibalism as a function of life stage. Relative species vulnerability to cannibalism, considering all life stages, was higher for C. undecimpunctata (0.55) than for C. vicina nilotica (0.45). Finally, linear regression was used to characterize the change in propensity for cannibalism between same-instar larval pairs as a function of prey density, which enabled determination of a theoretical upper prey threshold for each larval instar, i.e., the prey J Insect Behav (2015) 28:387-402 density beyond which no cannibalism would be expected. In both species, regressions for third and fourth instars did not intercept the X-axis, suggesting that some cannibalism by these stages was inevitable within the range of prey densities tested.
Cannibalism in Two Subtropical Lady Beetles Coleoptera Coccinellidae.pdf
Cannibalism is an important factor influencing both immature survival and adult reproductive success in aphidophagous lady beetles. This study employed three series of laboratory experiments to characterize life stage-specific cannibalism responses of Coccinella undecimpunctata L. and Cydonia vicina nilotica Mulsant to 1) different conspecific densities, with and without prey, 2) other life stages, and 3) various densities of prey, Myzus persicae Sulzer. All larval instars of both species cannibalized more in the absence of prey than in its presence at all conspecific densities, but in general, cannibalism increased with conspecific density only in the absence of prey, and more strongly for third and fourth instar C. undecimpunctata than for their C. vicina nilotica counterparts. Adults contributed the most cannibalism of any life stage, and eggs were the most vulnerable. In addition to cannibalizing their own and earlier instars, second and third instar C. undecimpunctata sometimes cannibalized third and fourth instars, respectively, and fourth instars occasionally ate pupae. Larvae of C. vicina nilotica were only preyed upon by the same or later stages and pupae, by adults, not fourth instars. A relative vulnerability index was calculated for each life stage based on its net vulnerability to cannibalism by all life stages and plotting these indices revealed species-specific patterns of diminishing vulnerability to cannibalism as a function of life stage. Relative species vulnerability to cannibalism, considering all life stages, was higher for C. undecimpunctata (0.55) than for C. vicina nilotica (0.45). Finally, linear regression was used to characterize the change in propensity for cannibalism between same-instar larval pairs as a function of prey density, which enabled determination of a theoretical upper prey threshold for each larval instar, i.e., the prey J Insect Behav (2015) 28:387-402 density beyond which no cannibalism would be expected. In both species, regressions for third and fourth instars did not intercept the X-axis, suggesting that some cannibalism by these stages was inevitable within the range of prey densities tested.
A comparative study of cannibalism and predation in seven species of flour beetle
Ecological Entomology, 2008
2. Variation among species in cannibalism and predation propensities did not reflect taxonomic affinities within the genus, indicating that these behaviours were shaped by ecology at species level. 3. Within species, larvae and adults displayed different propensities for cannibalism and predation, leading us to conclude that these behaviours evolve independently in the two life stages. 4. All species behaved as intraguild predators to some degree, especially in the adult stage. 5. Three general patterns of cannibalism and predation were described by principal component mapping and cluster analysis. 6. The first group comprised three cosmopolitan pest species that were more voracious as adults than as larvae; T. castaneum, T. confusum and T. destructor. It is proposed that stored product environments select for high adult voracity because the costs associated with emigration from such rare, but resource-rich, habitats intensifies interference competition among adults. 7. The second group consisted of species that inhabit natural environments and that were more voracious as larvae; T. anaphe, T. freemani and T. madens. Habitats for these species are likely numerous, but generally poor in quality, a situation that intensifies larval competition, while favouring earlier adult emigration. 8. The largest species, T. brevicornis, demonstrated inconsistent voracity between life stages and was the only species with chemically defended pupae. 9. It is proposed that consumption of eggs provides primarily nutritional benefits, whereas consumption of pupae has a more important role in interference competition.
Cannibalism is an important factor influencing both immature survival and adult reproductive success in aphidophagous lady beetles. This study employed three series of laboratory experiments to characterize life stage-specific cannibalism responses of Coccinella undecimpunctata L. and Cydonia vicina nilotica Mulsant to 1) different conspecific densities, with and without prey, 2) other life stages, and 3) various densities of prey, Myzus persicae Sulzer. All larval instars of both species cannibalized more in the absence of prey than in its presence at all conspecific densities, but in general, cannibalism increased with conspecific density only in the absence of prey, and more strongly for third and fourth instar C. undecimpunctata than for their C. vicina nilotica counterparts. Adults contributed the most cannibalism of any life stage, and eggs were the most vulnerable. In addition to cannibalizing their own and earlier instars, second and third instar C. undecimpunctata sometimes cannibalized third and fourth instars, respectively, and fourth instars occasionally ate pupae. Larvae of C. vicina nilotica were only preyed upon by the same or later stages and pupae, by adults, not fourth instars. A relative vulnerability index was calculated for each life stage based on its net vulnerability to cannibalism by all life stages and plotting these indices revealed species-specific patterns of diminishing vulnerability to cannibalism as a function of life stage. Relative species vulnerability to cannibalism, considering all life stages, was higher for C. undecimpunctata (0.55) than for C. vicina nilotica (0.45). Finally, linear regression was used to characterize the change in propensity for cannibalism between same-instar larval pairs as a function of prey density, which enabled determination of a theoretical upper prey threshold for each larval instar, i.e., the prey J Insect Behav
Cannibalism is one of the foremost imperative factors naturally occurring in the biological communities and is responsible for determining the population dynamics of a gigantic array of insects. A number of factors are held accountable for cannibalism explicitly, hunger, food availability, size disparity, density etc. Our study transacts with size disparity as the major factor shaping cannibalism among different larval combinations of two species of aphidophagous ladybird beetles namely, Cheilomenes sexmaculata and Coccinella transversalis. The results clearly discriminate that the degree of cannibalism augments when larvae of uneven size are kept together and the younger instars are at greater jeopardy in comparison to the older instars.
2014
Cannibalism is an important factor in biology and ecology of many species of insects and mites. The structure and dynamics of populations of predators used in biological control programs might be affected by cannibalism. The objective of the present study was to determine cannibalism by adult females of the generalist phytoseiids, Neoseiulus californicus (McGregor) and Typhlodromus bagdasarjani Wainstein & Arutunjan and the specialist predatory thrips, Scolothrips longicornis Priesner. The experiments were conducted under laboratory conditions at 25˚C, 65% RH and a photoperiod of 16h light: 8h dark. The larval stages, prepupae and pupae of the thrips and the immature stages (eggs, larvae and protonymphs) of the phytoseiids were used as prey. For this purpose, two types of experiments were carried out. In the first experiment, cannibalism of N. californicus, T. bagdasarjani and S. longicornis on their immatures were studied in the absence of the two-spotted spider mite (TSSM), Tetranychus urticae Koch as an extraguild (EG) prey. The second experiment determined the cannibalism of each adult female of the predatory mite and predatory thrips in presence of EG prey. Both phytoseiid species had ability to consume their conspecific prey and the predatory thrips had ability to consume conspecific larvae. Each female of N. californicus and T. bagdasarjani consumed the eggs (0.09 and 0.06 egg/ female/day, respectively), larvae (0.78 and 0.70 larva/female/day, respectively) and protonymphs (0.89 and 0.69 nymph/female/day, respectively). Also, S. longicornis consumed its first and second instar larvae (0.33 and 0.25 larva/female/day, respectively). When TSSM was presented as an extraguild prey, the intensity of cannibalism in N. californicus and T. bagdasarjani on their larvae 0.32 and 0.22 per day, respectively and on protonymphs 0.03 and 0.15 per day, respectively decreased and S. longicornis did not feed anymore on its own larval stages. Therefore, it is concluded that cannibalism is very limited in the three examined species and the lack of TSSM as the main prey can intensify this behavior.
Egyptian Journal of Biological Pest Control
Background Oenopia conglobata (Linnaeus) (Coleoptera: Coccinellidae) is a generalist predator feeding on several insect pests and utilized as a biological control agent in Türkiye. However, significant cannibalism has been observed among its different life stages under low food/prey availability. This study determined adult-egg, adult-larva, larva-egg, and larva-larva cannibalism of O. conglobata under laboratory conditions. Results Cannibalism among different life stages was observed under no supplemental diet (treatment group) or sufficient (100 Ephestia kuehniella eggs per individual) supplemental diet (control group). Fifty eggs per adult were provided to the 24 h-starved male and female adults for determining adult-egg cannibalism. Similarly, male, and female adults received 30 and 20 1st and 2nd instars, respectively to observe adult-larval cannibalism. Likewise, 10, 20, 30 and 40 eggs to 24-h starved 1st, 2nd, 3rd, and 4th instars, respectively were provided to record larval–...
TURKISH JOURNAL OF ZOOLOGY
Cannibalism or intraspecific predation, where one species feeds on individuals of its own species, is a widespread phenomenon in most aphidophagous coccinellids. Laboratory studies were conducted on the cannibalistic behavior of various developmental stages of Coccinella septempunctata L. (Coleoptera: Coccinellidae) in the presence and absence of natural food, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). In both the presence and absence of aphids, the eggs and 1st and 2nd instars of C. septempunctata were cannibalized by the adults, and the level was inversely related to the availability of aphids. The same was also true for cannibalism of eggs by larvae and within the larval stages, with older larvae consuming significantly higher numbers of eggs and younger larvae in the absence of aphids. The adults and 4th instar larvae also consumed a considerably higher number of eggs, even in the presence of aphids. Within the same stage/age of larvae, the level of cannibalism increased with each larval stage from minimum among 1st instars and maximum among 4th instars. The studies showed that a low density or scarcity of prey was the main cause of cannibalism in C. septempunctata.
Cannibalism of parasitoid-attacked conspecifics in a non-carnivorous caterpillar
Entomologia Experimentalis et Applicata, 2014
Cannibalism, the killing and consumption of conspecifics, can even occur in insect species typically considered to be non-carnivorous. Of particular interest is the cannibalism of parasitoid-attacked conspecifics, which could reduce parasitism levels in subsequent generations for that conspecific population. This study reports on the occurrence and some of the consequences of cannibalism in parasitoid-attacked obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). We show that larvae of C. rosaceana, which is considered to be an herbivorous caterpillar species, did not prey upon live conspecifics, but readily consumed conspecifics attacked by Habrobracon gelechiae Ashmead (Hymenoptera: Braconidae). Further examination found that C. rosaceana larvae feeding on parasitoid-attacked conspecifics, since their fourth instar, suffered a higher mortality and reduction in body size than those fed on plant material only. The cannibalism of attacked conspecifics did not appear to offer any nutrient benefits for the cannibal. To our best knowledge, this is the first empirical example of the occurrence and some of the consequences of cannibalism by a non-carnivorous insect on its parasitoid-attacked conspecifics. We discuss the adaptive significance of such cannibalism on parasitoid-attacked conspecifics with respect to a trans-generational fitness gain for the population through the killing of the parasitoids, thereby reducing parasitism in subsequent generations.
Isogroup Selection to Optimize Biocontrol Increases Cannibalism in Omnivorous (Zoophytophagous) Bugs
Insects, 2017
Abstract. Zoophytophagous insects can substitute animals for plant resources when prey is scarce. Many arthropods feed on conspecifics to survive in these conditions. An individual's tendency for cannibalism may depend on its genotype along with its diet specialization, in interaction with the availability of alternative food resources. We compared two isogroup lines of the zoophytophagous mullein bug, either specialized on animal or on plant diets, that were generated to improve biocontrol. We predicted that: (1) bugs from the prey-specialized line would show higher levels of cannibalism than bugs from the pollen-specialized line, and (2) both lines would decrease cannibalism levels in the presence of their preferred resource. Under laboratory conditions, large nymphal instars had 24 hours to feed on smaller instars, in the absence of additional resources, or with either spider mites or pollen present. Cannibalism was reduced by the availability of both prey and pollen, although prey had...