The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystem...The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystems, a field experiment was carried out in an experimental farm at Gembloux （Belgium） to study the effect of nettle margin strips on aphid and aphidophagous populations in close field crops, namely wheat （Triticum aestivum L.）, green pea （Pisum sativum L.） and rape （Brassicae napus L.）. The aphids and related beneficial populations were weekly assessed, from March to August 2005, by visual observations in two plots per field crop. A higher abundance of aphidophagous beneficials was collected in nettle strips when compared to the field crops. Particularly, the presence of predatory anthocorids, mirids and green lacewings was observed on nettle only. Nevertheless, the most abundant aphid predatory family, the Coccinellidae, was distributed in both environments, in nettle strips and in crop fields. The field margin supported a significantly higher density ofHarmonia axyridis than the field crops. In contrast, the field crops, green pea particularly, supported a higher density of Coccinella septempunctata. The distribution of the aphidophagous species, mainly the ladybirds, was discussed in relation to the host plant and related aphid species and their potential effect on integrated pest management.展开更多
Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey qual...Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey quality and intra- and interspecific interactions on their survival and development of life stages. Mortality of first instar ladybirds of both species was highest feeding on A. nerii. Preimaginal mortafity was lowest when feeding on L. erysimi （C. septempunctata, 1.6% and C. transversalis, 3.2%）, and highest when feeding on A. nerii （ C. septempunctata, 6.2% and C. transversalis, 8.2%）. Comparatively higher weight and larger size of C. septempunctata along with the lower levels of mortality recorded suggested that it is more likely to have acted as an intraguild predator than C. transversalis. High recorded mortality of C. transversalis is attributed to probable intraguild predation on account of its smaller size. The major sources of mortality were probably cannibalism, intraguild predation and other unknown factors. Lower prey quality increased the incidence of cannibalism and intraguild predation, especially in C. transversalis. The investigation suggests an intrinsic competitive advantage for C. septempunctata over C. transversalis in guilds of three aphid species.展开更多
The ladybird beetle Coccinella septempunctata(L.)is an important biocontrol agent of pests such as various aphid species.Despite being one of the most studied coccinellid species,many aspects of its foraging behavior ...The ladybird beetle Coccinella septempunctata(L.)is an important biocontrol agent of pests such as various aphid species.Despite being one of the most studied coccinellid species,many aspects of its foraging behavior are still not completely understood.This study focuses on the diel foraging behavior of C.septempunctata,investigating their olfactory orientation toward aphid-infested plants,walking activity on plants and on the soil,and feeding rates.In the scotophase the ladybird beetles were significantly more attracted to the odor of aphid-infested plants,on which they also showed considerably higher walking activity then on uninfested controls.Females were more prone to utilize olfactory cues when searching for prey and fed at higher rates than males;this shows that they are better adapted to nocturnal activity,as they require higher food intake.Coccinella septempunctata have the same feeding rate during the scotophase as in the photophase.Our study shows that C.septempunctata has the potential to forage in the scotophase if prey is abundant.The results support the hypothesis that volatiles of aphid-infested plants can attract or arrest foraging adult ladybird beetles,even in the darkness,which makes a considerable contribution to efficient prey search and enhances feeding capacity.展开更多
基金the Department of Higher Education,Government of Uttar Pradesh, India for providing financial assistance in the form of Centre of Excellence in Biocontrol of Insect Pests
文摘The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystems, a field experiment was carried out in an experimental farm at Gembloux （Belgium） to study the effect of nettle margin strips on aphid and aphidophagous populations in close field crops, namely wheat （Triticum aestivum L.）, green pea （Pisum sativum L.） and rape （Brassicae napus L.）. The aphids and related beneficial populations were weekly assessed, from March to August 2005, by visual observations in two plots per field crop. A higher abundance of aphidophagous beneficials was collected in nettle strips when compared to the field crops. Particularly, the presence of predatory anthocorids, mirids and green lacewings was observed on nettle only. Nevertheless, the most abundant aphid predatory family, the Coccinellidae, was distributed in both environments, in nettle strips and in crop fields. The field margin supported a significantly higher density ofHarmonia axyridis than the field crops. In contrast, the field crops, green pea particularly, supported a higher density of Coccinella septempunctata. The distribution of the aphidophagous species, mainly the ladybirds, was discussed in relation to the host plant and related aphid species and their potential effect on integrated pest management.
基金Department of Higher Education, Government of Uttar Pradesh, India for providing financial assistance in the form of Centre of Excellence in Biocontrol of Insect Pests.
文摘Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey quality and intra- and interspecific interactions on their survival and development of life stages. Mortality of first instar ladybirds of both species was highest feeding on A. nerii. Preimaginal mortafity was lowest when feeding on L. erysimi （C. septempunctata, 1.6% and C. transversalis, 3.2%）, and highest when feeding on A. nerii （ C. septempunctata, 6.2% and C. transversalis, 8.2%）. Comparatively higher weight and larger size of C. septempunctata along with the lower levels of mortality recorded suggested that it is more likely to have acted as an intraguild predator than C. transversalis. High recorded mortality of C. transversalis is attributed to probable intraguild predation on account of its smaller size. The major sources of mortality were probably cannibalism, intraguild predation and other unknown factors. Lower prey quality increased the incidence of cannibalism and intraguild predation, especially in C. transversalis. The investigation suggests an intrinsic competitive advantage for C. septempunctata over C. transversalis in guilds of three aphid species.
基金the Swedish Research Council for Environment,Agricultural Sciences and Spatial Planning(FORMAS)(project number 220-2014-225 and project number 220-214-495).
文摘The ladybird beetle Coccinella septempunctata(L.)is an important biocontrol agent of pests such as various aphid species.Despite being one of the most studied coccinellid species,many aspects of its foraging behavior are still not completely understood.This study focuses on the diel foraging behavior of C.septempunctata,investigating their olfactory orientation toward aphid-infested plants,walking activity on plants and on the soil,and feeding rates.In the scotophase the ladybird beetles were significantly more attracted to the odor of aphid-infested plants,on which they also showed considerably higher walking activity then on uninfested controls.Females were more prone to utilize olfactory cues when searching for prey and fed at higher rates than males;this shows that they are better adapted to nocturnal activity,as they require higher food intake.Coccinella septempunctata have the same feeding rate during the scotophase as in the photophase.Our study shows that C.septempunctata has the potential to forage in the scotophase if prey is abundant.The results support the hypothesis that volatiles of aphid-infested plants can attract or arrest foraging adult ladybird beetles,even in the darkness,which makes a considerable contribution to efficient prey search and enhances feeding capacity.
