L‘élevage de deux coccinelles Harmonia axyridis et Semiadalia undecimnotataà l'aide d'oeufs d’Anagasta kuehniella tués aux rayons ultraviolets

Abstract. For polyphagous predators, the link between food consumption and reproduction is not always straightforward, and instead may reflect that even predators with very broad diets may have reproductive tactics that are tied to consumption of a restricted range of prey. We studied the consumption and use of two prey species for reproduction by the ladybird, Harmonia axyridis Pallas. This polyphagous predator feeds on both pea aphids [Acyrthosiphon pisum (Harris)] and larvae of the alfalfa weevil [Hypera postica (Gyllenhal)] that it encounters when foraging in alfalfa fields. When provided a diet of pea aphids or of alfalfa weevils and/or sugar water, females of H. axyridis laid eggs in large numbers only on the diet of aphids. Females laid no eggs on diets of weevils or sugar alone, and laid only small numbers of eggs when the two foods were provided together. When placed on a diet of aphids, females began laying eggs earlier, and laid more eggs altogether, when they had previously fed on weevils versus sugar water. The predators' consumption rates of aphids were greater than their consumption rates of weevils, and they produced less frass per mg of prey consumed on an aphid versus weevil diet. The predators searched more actively when maintained on a weevil versus aphid diet. Hence, lower rates of food intake and assimilation, and greater allocation of nutrients and energy to searching, appear to contribute to the reduced egg production of H. axyridis females that feed on weevils versus aphids. Alfalfa weevils are also less suitable prey than pea aphids for larval survival and development of H. axyridis. Thus, the differing responses of H. axyridis adults to these two prey types may reflect that these predators are well adapted in the linking of their feeding and reproductive behavi or.

Section: Discussionmentioning

confidence: 99%

The link between food and reproduction in aphidophagous predators: a case study with Harmonia axyridis (Coleoptera: Coccinellidae)

Evans¹,

Gunther²

2005

“…The polyphagous species C. maculata, for example, produces very large numbers of eggs in the laboratory when it feeds on eggs of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Hazzard & Ferro, 1991;Munyaneza & Obrycki, 1997) or the European corn borer, Ostrinia nubilalis (Hubner) (Phoofolo & Obrycki, 1997), foods that it is known to feed on in natural settings. Harmonia axyridis (Pallas) produces eggs at high rates when fed eggs of the lepidopteran Ephestia (Anagasta) kuehniella Zeller (Schanderl et al, 1988). The prey is a pest of stored products that this predator would not encounter naturally, but its reproductive response may reflect that it does often exploit similar prey as well as aphids in nature.…”

Section: Additional Questionsmentioning

confidence: 99%

Searching and reproductive behaviour of female aphidophagous ladybirds (Coleoptera: Coccinellidae): a review

Evans¹

2003

114

Abstract. In searching both for food to produce eggs and for suitable oviposition sites, females of aphidophagous ladybirds must be adapted to exploit prey that vary greatly in their occurrence and abundance over both space and time. A simple model of ladybird searching and oviposition behaviour emerged in the 1950s: adult ladybirds are highly mobile in traversing the landscape, but become less active and produce more eggs as their rate of aphid consumption increases. The net result is that most eggs tend to be laid at sites of high aphid density. Laboratory and field experiments and observations over the past several decades have generally sup ported this basic model, although the linkage between ladybird dispersal activity and local aphid density often appears to be rela tively weak.

“…Laboratory tests have shown that it is a powerful biological agent for use against many phytophagous species. That this ladybird beetle can be successfully reared on the eggs of Ephestia kuehniella Zeller (Schanderl et al, 1988) makes it easy to produce in large number for inundative releases. However, its negative impact on native ladybird beetles and other non-target arthropods is rarely studied (c.f.…”

Section: Introductionmentioning

confidence: 99%

“…It is a very polymorphic ladybeetle in which some of the phenotypes differ in fitness (Soares et al, 2001(Soares et al, , 2003. This euryphagous predator prefers aphids (Hukusima & Kamei, 1970;Iablokoff-Khnzorian, 1982;Osawa, 1992), but can feed on psyllids (Fye, 1981;Drea & Gordon, 1990), coccids (McLure, 1987;Hodek & Hon k, 1996), immature stages and eggs of Lepidoptera (Schanderl et al, 1988;Drea & Gordon, 1990) and spider mites (Drea & Gordon, 1990;Lucas et al, 1997a). Laboratory tests have shown that it is a powerful biological agent for use against many phytophagous species.…”

Section: Introductionmentioning

confidence: 99%

Intraguild predation between the aphidophagous ladybird beetles Harmonia axyridis and Coccinella undecimpunctata (Coleoptera: Coccinellidae): the role of body weight

Félix¹,

Soares²

2004

Abstract. The magnitude, direction and symmetry of intraguild predation (IGP) between the developmental stages of the aphidophagous Harmonia axyridis Pallas and Coccinella undecimpunctata L. were characterized and compared. Mobility and body weight were the main factors affecting the magnitude of IGP.H. axyridis was more often the predator than C. undecimpunctata and eggs the most vulnerable developmental stage. There was significant asymmetrical IGP on eggs by the second and later, and fourth larval stages of H. axyridis and C. undecimpunctata, respectively. Asymmetrical IGP of pupae was only recorded for the fourth larval stage of H. axyridis. There was no IGP between adults, but larvae of both species attacked heterospecifics. The best model of the relationship between rate of predation and the difference in the body weight of IG predator and prey differs for the two ladybirds. A small difference in the body weights leads to a marked increase in the rate of predation in H. axyridis but not in C. undecimpunctata. In asymmetrical combinations, increase in body weight of the intraguild predator did not significantly increase the rate of predation. Mobility and body weight were not the only important parameters involved in the symmetry of IGP. Aggressive behaviour of H. axyridis negatively affected the survival of C. undecimpunctata.