Intraguild predation between an introduced lady beetle, Harmonia axyridis (Coleoptera: Coccinellidae), and a native lady beetle, Coleomegilla maculata (Coleoptera: Coccinellidae).
1998; Kansas (Central States) Entomological Society; Volume: 71; Issue: 2 Linguagem: Inglês
ISSN
1937-2353
AutoresTed E. Cottrell, Kenneth V. Yeargan,
Tópico(s)Insect Resistance and Genetics
ResumoThe introduction of the multicolored Asian lady beetle, Harmonio axyridis Pallas (Cole?ptera: Coccinellidae), to the United States has led to its interaction with native coccinellid species. Harmon?a axyridis adults and larvae co-occur temporally and spatially with adults and larvae of the native species, Coleomegilla maculata (DeGeer), which is the most abundant coccinellid species on sweet corn in Kentucky. We tested the capability of H. axyridis to develop on a diet of only C. maculata eggs and the propensity for either species to prey upon the other. We found that H. axyridis larvae can complete development on a diet of only C. maculata eggs and that pr?dation between H. axyridis and C. maculata larvae usu ally results in H. axyridis eating C. maculata. The multicolored Asian lady beetle (Harmonio axyridis Pallas [Cole?ptera: Coc cinellidae]) was introduced into the United States as a biological control agent of several arboreal homopteran pests. Repeated releases of H. axyridis were made in several states starting in 1916, and now this beetle is found throughout much of the United States (Gordon, 1985; Tedders and Schaefer, 1994; LaMana and Miller, 1996). Since the first detection ofH. axyridis in Kentucky during 1992, it has been found in that state on tobacco (Nicotiana tabacum L.) and sweet corn (Zea mays L.) (Pfan nenstiel, 1995; Cottrell and Yeargan, 1998a, b), in addition to arboreal habitats. Dur ing our field studies on the native lady beetle Coleomegilla maculata (DeGeer) in sweet corn, we noted that H. axyridis (adults and larvae combined) was the second most frequently observed predator species feeding on C. maculata eggs on sweet corn (Cottrell and Yeargan, 1998a, b). Additionally, an observation was made of a late-instar H axyridis eating a late-instar C. maculata on sweet corn in the field (T. E. Cottrell, pers. obs.). In the laboratory, when reared in petri dishes with food and water provided ad li bitum, approximately ten C maculata larvae could be kept in single 9-cm-diameter petri dishes through pupation with little or no cannibalism. However, when H axyridis larvae were reared in this manner, cannibalism sometimes occurred, even though excess food was provided (T. E. Cottrell, pers. obs.). From our field and lab oratory observations, H axyridis larvae appeared more aggressive than C maculata larvae. Our primary objective was to determine, under controlled conditions, the out come of intraguild pr?dation between these coccinellid species. We also determined whether the invading species could utililize eggs of the native species as a food source. Finally, as an index of relative aggressiveness of the two species, we exam ined the tendency of each species to cannibalize similar-sized larvae. 1 Current address: United States Department of Agriculture-Agricultural Research Service, South eastern Fruit and Tree Nut Research Laboratory, 21 Dunbar Road, Byron, Georgia 31008. Accepted for publication 26 October 1998. This content downloaded from 157.55.39.215 on Wed, 31 Aug 2016 04:08:37 UTC All use subject to http://about.jstor.org/terms 160 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY Materials and Methods Laboratory colonies of both H. axyridis and C. maculata were started from adult beetles collected near Lexington, KY. These colonies were used for collection of eggs and larvae used in pr?dation and cannibalism studies. Colonies were maintained at 27 ? 1?C and a photoperiod of 15:9 (L:D) hr in an environmental chamber. Indi vidual adults were kept in 9-cm-diameter petri dishes and provided a blended beef diet (100 g beef liver, 100 g ground beef, and 12 ml of 5% sucrose [wt/vol]) wrapped in laboratory film (Parafilm M' American Can Company, Greenwich, CT) (Cohen, 1985). The diet of//, axyridis adults was occasionally supplemented with Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) eggs to increase the beetles' egg production. Water was provided by placing a moistened, cotton dental wick in the petri dish. Green floral paper was cut into 10-cm-diameter circles and used to line lids of petri dishes containing adult, female coccinellids. This paper provided females with an oviposi tional substrate which was easily removed and replaced. Egg clusters were collected daily. Helicoverpa zea eggs were collected from a laboratory colony maintained by methods modified from Ignoffo (1965) at 15:9 (L:D) hr and room temperature. Pr?dation of C. maculata eggs by H. axyridis was examined by placing 30 unfed first-instar H. axyridis larvae individually into 9-cm-diameter petri dishes with a moistened cotton dental wick for a water source, and providing C. maculata eggs, ad libitum, daily. Data were recorded for number of larvae surviving through each instar, pupal stage, and for emerged adults. To obtain larvae of the appropriate size or instar for our studies of larval pr?da tion and cannibalism, larvae of both species were reared singly in 9-cm-diameter petri dishes at 15:9 (L:D) hr and 27 ? 1?C with H. zea eggs ad libitum for food and a moistened cotton dental wick for a water source. All pr?dation and cannibalism experiments were done in 9-cm-diameter petri dishes in environmental chambers at 15:9 (L:D) hr and 27 ? 1?C. No food or water was provided during the intraguild pr?dation or cannibalism experiments, but an open container of water was placed at the bottom of the incubator to increase humidity. Thirty-one second-instar H. axyridis were paired with second-instar C. maculata and, after 24 hr, numbers of live and eaten larvae of each species were recorded. A 2 x 2 contingency table was used to compare totals for live and eaten H. axyridis with live and eaten C. maculata. We used Yates' correction for continuity to calculate %2 because the degrees of freedom = 1 (Zar, 1996). Intraguild pr?dation was examined and analyzed in the same man ner for the following combinations of H. axyridis and C. maculata: fourth-instar H. axyridis versus fourth-instar C. maculata (N = 35 pairs) and first-instar H. axyridis versus third-instar C. maculata (N = 36 pairs). In addition to testing intraguild pr? dation between specific instars, we also tested it for individuals that were similar in size. For that experiment we weighed third-instar H. axyridis and fourth-instar C. maculata using a Mettler AE 163 balance (Mettler-Toledo, Inc., Worthington, OH), and 31 H. axyridis third instars were paired with similar-weight C. maculata fourth instars. Because these individuals were similar in size, we felt that they might require a longer period to engage in intraguild pr?dation. Thus, data were recorded at 24 hr and again at 96 hr, and results were analyzed for each time as previously described. Twenty pairs of fourth-instar C. maculata were set up as described for intraguild pr?dation experiments above and cannibalism was recorded after 24 hr. Similarly, 36 pairs of fourth-instar H. axyridis were examined after 24 hr and cannibalism was recorded. This content downloaded from 157.55.39.215 on Wed, 31 Aug 2016 04:08:37 UTC All use subject to http://about.jstor.org/terms VOLUME 71, ISSUE 2 161 Table 1. Laboratory study of interspecific pr?dation and cannibalism by H. axyridis and C. maculata. Combination Duration Result 2nd instar H. axyridis vs. 2nd instar C. maculata 4th instar H. axyridis vs. 4th instar C. maculata 1st instar H. axyridis vs. 3rd instar C. maculata 3rd instar H. axyridis vs. 4th instar C. maculata 4th instar C. maculata vs. 4th instar C. maculata 4th instar H. axyridis vs. 4th instar H. axyridis 24 hr 86.7% pr?dation on C. maculata 0.0% pr?dation on H. axyridis 24 hr 94.3% pr?dation on C. maculata 0.0% pr?dation on H. axyridis 24 hr 0.0% pr?dation on C. maculata 68.6% pr?dation on H. axyridis 24 hr 16.1% pr?dation on C. maculata 3.2% pr?dation on H. axyridis 96 hr 93.1% pr?dation on C. maculata 6.9% pr?dation on H. axyridis 24 hr 5.0% cannibalism 24 hr 33.3% cannibalism
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