| Global warming is a reality and it now is changing the structure and functioning of various ecosystems.Previous studies have mostly addressed the warming effect on the species dynamics and diversity of plant communities but not animal communities.In particular,there are few experimental studies exploring the community consequence of global warming.In this study,a manipulative experiment was conducted to determine the potential response of main taxa of insects to global warming in Hongyuan alpine meadow.Large Open Top Chambers(OTCs,15 m x 15 m x 2.5m)with sides made of glass were used for warming treatment,while those with sides made of steel sheet(mesh size<0.1 mm)were used for Control.I investigated species abundance for the insect taxa including Tephritid flies(Tephritidae,Diptera),hoverflies(Syrphidae,Diptera),sawtlies(Tenthredinidae,Hymenoptera),capsid bugs(Miridae,Hemiptera),snout moths(Pyralidae,Lepidoptera),mosquitoes(Culicidae,Diptera),horseflies(Tabanidae,Diptera).Our results are shown as follows.Mean annual temperature of air was 0.9? higher,mean annual temperature at soil surface was 1.34? higher,and soil moisture at-5cm was 5.82%higher in the warmed OTCs than the control.Moreover,the temperature increases were much higher in non-growing seasons(1.1?,1.9?,and 6.06%,respectively)than in growing seasons(0.51 ?,0.47?,and 5.41%,repectively).Warming had diverse effects on the peak time of insect abundance.In 2017,Tephritid flies,hoverflies,capsid bugs and snout moths advanced the peak time approximately by 9,11,5 and 5 days,and sawflies showed a delay of ca.15days.Furthermore,warming showed no remarkable influence on the peak time of mosquitoes and horseflies.However,no apparent change in the above parameters was observed in 2016.The response of species abundance to warming varied with insect taxon.In 2016,the estimated number of Tephritid flies and capsid bugs were 80.3 and 111 per chamber in the warming treatment,1.4 and 3.4 times more than the controls.The estimated number of sawflies and snout moths was 7.7 and 23,0.4 and 0.6 times smaller than those in the control chamber(13.7 and 51.6 per chamber,respectively).Nevertheless,warming unchanged the abundances of hoverflies,mosquitoes and horseflies(P>0.05 for all).In 2017,the estimated number of Tephritid flies,capsid bugs and hoverflies were 384.3,401,246 per chamber in the warming treatment,significantly larger than those(142.7,96.3,197.3 per chamber,respectively)in the control.The estimated number of snout moths,mosquitoes and horseflies were 3,112,115.5 per chamber in the warming treatment,significantly smaller than those(29.3,154,311.8)in the control.Nevertheless,the warming effect was non-significant on the abundance of sawflies(P=0.655).The response of species abundance to warming also varied with insect functional type The abundance of herbivores was 449 and 561per chamber in 2016 and was 1283 and 1855 per chamber in 2017 for the warming treatment and the control,respectively.The abundance of predators was 392 and 305 per chamber in 2016,but in 2017 the warming effect was non-significant(P=0.292).In summary,the preliminary results show that global warming may have contrasting effect on species abundance among insect taxa and among insect functional groups.The results may improve understanding how the insect community responds to global warming,and also valuable for biodiversity conservation and grassland management. |
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