The Effects Of Colony Density, Food Availability, And Environmental Noise On Acoustic Characteristic Of Acheta Domesticus

Insects are the group that includes the biggest animal species on the earth,and these insects often communicate each other by using physical and chemical ways.Vocalization is an universal phenomena of physical communication in insects,and plays an important role in intraspecific and interspecific communication among insects.Acoustic communication in Orthoptera can convey information that determines sexual selection,competition,attack,contact,alarm,etc.Moreover,acoustic communication is an important basis for species classification.Generally speaking,insect acoustic is relative stable in intraspecific communication.However,insect acoustic characteristics may slightly or even significantly change under changeable environmental factors.A growing of studies has found that environment factors,such as photoperiod,food and temperature changes strongly affect insect acoustic characteristics.Acheta domesticus belongs to Orthoptera,cricket family.Female crickets don't have ability of acoustic communication,and male crickets have the ability of acoustic communication by rubbing the specialized structure of the two wings.Until now,most studies about acoustic communication of male cricket have been mainly concentrated on the acoustic mechanism.However,the recognition of how environmental factors affect acoustic characterisitics is poorly understood.Therefore,in this study,the manipulated experiment with different colony density,feed intake,and environmental noise treatments was conducted to examine the effects of these three factors on acoustic characterisitics of A.domesticus,which further reveals the effects of environmental factors on acoustic characterisitics of insects.It is also important for understanding acoustic communication of insects and for the adaptation of insects to changeable environment.In this study,A.domesticus were raised under different colony density treatments(overall density and the same total amounts but different amounts of male and female),feed intake treatments(high feed intake and low feed intake),and noise treatments(high noise and normal noise).We recorded and analyzed the sound samples.Furthermore,we observed,measured and completed the acoustic relative morphological indexes' statistical analysis.The main conclusions are as follows:(1)Colony density treatments had a significant impact on cricket acoustic time-domain characteristics.In the overall treatments,pulse duration of male crickets in 200 treatments was significantly lower than that of the 50 treatments,but interchirp duration of 200 was significantly higher than that of the two 150 and 50 treatments.Under 80 treatments,the pulse duration 1,pulse duration 2,pulse duration and chirp duration were significant higher than that of the other three treatments.However,the interchirp duration of 80 treatment was significant lower than that of the other three treatments.Although there were significant correlations between some time-domain characteristics and some stridulation structures,changed stridulation structures couldn't explain the responses of time-domain characteristics to environmental factors.Results showed that male weight under the high density treatments was significantly higher than that of low density treatments,and the body weight change can't explain chirp characteristic changes.Therefore,the change of male acoustic characteristics may be caused by resource allocation differences or selection pressure under the treatments of overall density.Proportion of male to female amounts(M:F=3:8,and M:F=8:3)had a significant impact on crickets' acoustic time-domain characteristics.The pulse duration 1,pulse duration 2,and pulseduration of 80 treatments were significantly higher than that of 30 treatments.But the interchirp duration and pulse interval of 30 treatments were significantly higher than that of 80 treatments.Regression analysis showed that there was no correlation between the time-domain characteristics and stridulation indexes,as well as other morphological characteristics.Consequently,the change of time-domain characteristics may be caused by the adjustment of short-term behavior when A.domesticus male and female quantitative proportion was different.(2)Environmental noise treatments had a significant impact on crickets' acoustic time-domain characteristics.The interchirp duration of crickets in high noise treatments was lower than that of normal noise treatments.Statistical analysis showed no significant difference between male stridulation and relative morphological indicators.Meanwhile,regression analysis showed no correlation between the interchirp duration and stridulation strucuture,as well as other morphological properties.Although there was a negative correlation relationship between teeth counted and some time-domain characteristics,changed stridulation structures did not explain the responses of time-domain characteristics to environmental factors.As a consequence,the change of acoustic time-domain characteristics may be the reaction of short-term behavior caused by environmental noise treatment for crickets to adapt to environment noise coverage.(3)Feed intake treatments had a significant impact on crickets' acoustic time-domain characteristics.Pulse duration 1 of crickets in high feed intake treatments was significantly higher than that of low feed intake,but interchirp duration of high feed intake was significantly lower than that of low feed intake.There was no significant difference in stridulation characteristics,as well as other morphological indicators.Regression analysis results showed there was a negative correlation relationship between body length and some time-domain characteristics.At the same time,there was a negative correlation relationship between body weight and pulse duration 2.However,significant changed pulse duration 1 and interchirp duration under feed intake treatment had no correlation with stridulation indicators,as well as other morphological indexes.As a consequence,the change of acoustic time-domain characteristics under feed intake treatments may be the influence of short-term food restrictions.In summary,colony density treatments,environmental noise treatments and feed intake treatments had significant effects on A.domesticus male acoustic characteristics.However,the mechanism of the acoustic characteristics changes induced by environmental changes is not very clear.So,the mechanism still needs further research for discussion.In fact,the changes of acoustic characteristics play an important role in defense,intraspecific competition,and sexual selection among insects.Particularly,the short-term behavior reaction to environmental changes is the reflection of the insects adaption strategies,which is of great significance for deeply understanding the crickets acoustic communication as well as adaptive strategies.Meanwhile,it provides the theoretical basis for further exploring female sexual selection induced by the environmental changes.