Field observations were carried out between 2002 and 2005 on bio-ecology of white grubs infesting teak （Tectona grandis Linn. f.） seedlings at Ramdongari Forest Nursery, Forest Development Corporation of Maharashtra...Field observations were carried out between 2002 and 2005 on bio-ecology of white grubs infesting teak （Tectona grandis Linn. f.） seedlings at Ramdongari Forest Nursery, Forest Development Corporation of Maharashtra, Nagpur in central India. The study collected the data required for an integrated pest management strategy against the white grubs. The species damaging teak seedlings were Holotrichia rustica （Burmeister） and H. mucida Gyllenhal. The beetles （adults） of both these species began to emerge just after the pre-monsoon showers and when the relative humidity had risen rapidly over several days, but before the first monsoon rains. While the adults fed and mated on naturally growing bushes of Ziziphus jujuba, Z mauritiana, Z. xylopyra, Acacia leucophloea and A. catechu immediately after the emergence from the teak beds in the nursery, the immature stages （grubs） of both species fed on roots of the teak seedling, leading to plant death. This is the first report of （i） damage caused to teak seedlings by grubs ofH. rustica and H. mucida, and （ii） of Z.jujuba and Z. mauritiana being hosts for the beetles ofH. mucida and H, rustica. It is also the first detailed report on the field bio-ecology of the H. rustica and H. mucida as major pests ofteak. White grubs are among the toughest-to-manage pests of economic importance and information presented here on the pest incidence and damage ofH. rustica and H. mucida is important to researchers and nursery field managers for the management of these pests on teak.展开更多
Rose chafer beetles(Protetia cuprea)are pollinators as well as agricultural pests,flying between flowers and trees while foraging for pollen and fruits.Calculating the energy they expend on flying during foraging acti...Rose chafer beetles(Protetia cuprea)are pollinators as well as agricultural pests,flying between flowers and trees while foraging for pollen and fruits.Calculating the energy they expend on flying during foraging activity faces the challenge of measuring the metabolic rate(MR)of free-flying insects in an open space.We overcame this challenge by using the bolus injection of ^(13)C Na-bicarbonate technique to measure their metabolic energy expenditure while flying in a large flight arena.Concurrently,we tracked the insects with high-speed cameras to extract their flight trajectory,from which we calculated the mechanical power invested in flying for each flight bout.We found that the chemical(metabolic)energy input converted to mechanical flight energy output at a mean efficiency of 10.4%±5.2%,with a trend of increased efficiency in larger conspecifics(efficiency scaled with body mass to the power of 1.4).The transition in the summer from a diet of pollen to that of fruits may affect the energy budget available for foraging.Starved P.cuprea,feeding on apples ad libitum,increased their body mass by an average of 6%in 2 h.According to our calculations,such a meal can power a 630-m flight(assuming a carbohydrate assimilation efficiency of 90%).Pollen,with a low water and carbohydrate content but rich in proteins and lipids,has a higher caloric content and should assimilate differently when converting food to flight fuel.The high cost of aerial locomotion is inherent to the foraging behavior of rose chafers,explaining their short flight bouts followed by prolonged feeding activity.展开更多
文摘Field observations were carried out between 2002 and 2005 on bio-ecology of white grubs infesting teak （Tectona grandis Linn. f.） seedlings at Ramdongari Forest Nursery, Forest Development Corporation of Maharashtra, Nagpur in central India. The study collected the data required for an integrated pest management strategy against the white grubs. The species damaging teak seedlings were Holotrichia rustica （Burmeister） and H. mucida Gyllenhal. The beetles （adults） of both these species began to emerge just after the pre-monsoon showers and when the relative humidity had risen rapidly over several days, but before the first monsoon rains. While the adults fed and mated on naturally growing bushes of Ziziphus jujuba, Z mauritiana, Z. xylopyra, Acacia leucophloea and A. catechu immediately after the emergence from the teak beds in the nursery, the immature stages （grubs） of both species fed on roots of the teak seedling, leading to plant death. This is the first report of （i） damage caused to teak seedlings by grubs ofH. rustica and H. mucida, and （ii） of Z.jujuba and Z. mauritiana being hosts for the beetles ofH. mucida and H, rustica. It is also the first detailed report on the field bio-ecology of the H. rustica and H. mucida as major pests ofteak. White grubs are among the toughest-to-manage pests of economic importance and information presented here on the pest incidence and damage ofH. rustica and H. mucida is important to researchers and nursery field managers for the management of these pests on teak.
文摘Rose chafer beetles(Protetia cuprea)are pollinators as well as agricultural pests,flying between flowers and trees while foraging for pollen and fruits.Calculating the energy they expend on flying during foraging activity faces the challenge of measuring the metabolic rate(MR)of free-flying insects in an open space.We overcame this challenge by using the bolus injection of ^(13)C Na-bicarbonate technique to measure their metabolic energy expenditure while flying in a large flight arena.Concurrently,we tracked the insects with high-speed cameras to extract their flight trajectory,from which we calculated the mechanical power invested in flying for each flight bout.We found that the chemical(metabolic)energy input converted to mechanical flight energy output at a mean efficiency of 10.4%±5.2%,with a trend of increased efficiency in larger conspecifics(efficiency scaled with body mass to the power of 1.4).The transition in the summer from a diet of pollen to that of fruits may affect the energy budget available for foraging.Starved P.cuprea,feeding on apples ad libitum,increased their body mass by an average of 6%in 2 h.According to our calculations,such a meal can power a 630-m flight(assuming a carbohydrate assimilation efficiency of 90%).Pollen,with a low water and carbohydrate content but rich in proteins and lipids,has a higher caloric content and should assimilate differently when converting food to flight fuel.The high cost of aerial locomotion is inherent to the foraging behavior of rose chafers,explaining their short flight bouts followed by prolonged feeding activity.
