After the outbreak of Dendrolimus superans Buter in 2002, many insect borers quickly invaded larch （Larix gmelinii Rupr.） forests in the Aershan of Inner Mongolia. Methods involved included setting sample plots, col...After the outbreak of Dendrolimus superans Buter in 2002, many insect borers quickly invaded larch （Larix gmelinii Rupr.） forests in the Aershan of Inner Mongolia. Methods involved included setting sample plots, collecting adults in iron traps and measuring areas of galleries to study the invasive sequence, their ecological niche and the extent of the different effects by the main insect borers to their hosts. The results showed that the damage of D. superans weakened L. gmelinii, first Ips subelongatus Motschulsky invaded, followed by Acanthocinus carinulatus Gebler, Monochamus urussovi Fisher and M. sutor L. After the outbreak of D. superans, the average density of longhorn beetles per L. gmelinii tree increased. The ecological niche of Ips subelongatus stretches almost from the base to the top of the trunk. The number of insects in older stands of L. gmelinii is larger than those in middle aged stands. They do not damage healthy trees of L. gmelinii. The ecological niche of A. carinulatus is higher in dead L. gmelinii trees than in weak ones. The degree of damage is directly proportional with age and depth of bark. M. urussovi mainly damages trunks below 4 m in weak trees; in dead trees they can do damage up to 6 m in height. M. sutor mainly damages trunks below 5 m in weak L. gmelinii trees; in dead trees they cause damage up to 7 m. Again, the degree of damage is directly proportional with age. None of the three species of longhorn beetles damage healthy L. gmelinii and younger trees. Among the main insect borers, the degree of damage caused by I. subelongatus is more serious than that of other insects.展开更多
Aphids are phloem-feeding insects that reduce crop productivity due to feeding and transmission of plant viruses.When aphids disperse across the landscape to colonize new host plants,they will often probe on a wide va...Aphids are phloem-feeding insects that reduce crop productivity due to feeding and transmission of plant viruses.When aphids disperse across the landscape to colonize new host plants,they will often probe on a wide variety of nonhost plants before settling on a host suitable for feeding and reproduction.There is limited understanding of the diversity of plants that aphids probe on within a landscape,and characterizing this diversity can help us better understand host use patterns of aphids.Here,we used gut content analysis(GCA)to identify plant genera that were probed by aphid vectors of potato virus Y(PVY).Aphids were trapped weekly near potato fields during the growing seasons of 2020 and 2021 in San Luis Valley in Colorado.High-throughput sequencing of plant barcoding genes,trnF and ITS2,from 200 individual alate(i.e.,winged)aphids representing nine vector species of PVY was performed using the PacBio sequencing platform,and sequences were identi-fied to genus using NCBI BLASTn.We found that 34.7%of aphids probed upon presumed PVY host plants and that two of the most frequently detected plant genera,Solanum and Brassica,represent important crops and weeds within the study region.We found that 75%of aphids frequently probed upon PVY nonhosts including many species that are outside of their reported host ranges.Additionally,19%of aphids probed upon more than one plant species.This study provides the first evidence from high-throughput molecular GCA of aphids and reveals host use patterns that are relevant for PVY epidemiology.展开更多
文摘After the outbreak of Dendrolimus superans Buter in 2002, many insect borers quickly invaded larch （Larix gmelinii Rupr.） forests in the Aershan of Inner Mongolia. Methods involved included setting sample plots, collecting adults in iron traps and measuring areas of galleries to study the invasive sequence, their ecological niche and the extent of the different effects by the main insect borers to their hosts. The results showed that the damage of D. superans weakened L. gmelinii, first Ips subelongatus Motschulsky invaded, followed by Acanthocinus carinulatus Gebler, Monochamus urussovi Fisher and M. sutor L. After the outbreak of D. superans, the average density of longhorn beetles per L. gmelinii tree increased. The ecological niche of Ips subelongatus stretches almost from the base to the top of the trunk. The number of insects in older stands of L. gmelinii is larger than those in middle aged stands. They do not damage healthy trees of L. gmelinii. The ecological niche of A. carinulatus is higher in dead L. gmelinii trees than in weak ones. The degree of damage is directly proportional with age and depth of bark. M. urussovi mainly damages trunks below 4 m in weak trees; in dead trees they can do damage up to 6 m in height. M. sutor mainly damages trunks below 5 m in weak L. gmelinii trees; in dead trees they cause damage up to 7 m. Again, the degree of damage is directly proportional with age. None of the three species of longhorn beetles damage healthy L. gmelinii and younger trees. Among the main insect borers, the degree of damage caused by I. subelongatus is more serious than that of other insects.
文摘Aphids are phloem-feeding insects that reduce crop productivity due to feeding and transmission of plant viruses.When aphids disperse across the landscape to colonize new host plants,they will often probe on a wide variety of nonhost plants before settling on a host suitable for feeding and reproduction.There is limited understanding of the diversity of plants that aphids probe on within a landscape,and characterizing this diversity can help us better understand host use patterns of aphids.Here,we used gut content analysis(GCA)to identify plant genera that were probed by aphid vectors of potato virus Y(PVY).Aphids were trapped weekly near potato fields during the growing seasons of 2020 and 2021 in San Luis Valley in Colorado.High-throughput sequencing of plant barcoding genes,trnF and ITS2,from 200 individual alate(i.e.,winged)aphids representing nine vector species of PVY was performed using the PacBio sequencing platform,and sequences were identi-fied to genus using NCBI BLASTn.We found that 34.7%of aphids probed upon presumed PVY host plants and that two of the most frequently detected plant genera,Solanum and Brassica,represent important crops and weeds within the study region.We found that 75%of aphids frequently probed upon PVY nonhosts including many species that are outside of their reported host ranges.Additionally,19%of aphids probed upon more than one plant species.This study provides the first evidence from high-throughput molecular GCA of aphids and reveals host use patterns that are relevant for PVY epidemiology.
