Courtship behaviour in the Great Green Bush-Cricket species, Tettigonia viridissima, involves male crickets producing different vocalizations (songs) to:
Scientists investigated bush-cricket courtship behaviour by exposing a population of sexually active male bush-crickets to a sublethal concentration of a glyphosate-based herbicide (GLY). They also maintained a separate control population of sexually active male bush-crickets under identical conditions but without GLY exposure.
They determined the percentage of males making calling songs or rivalry songs in each population.
Table 1 shows their results.
| Population | Percentage of males making calling songs (%) | Percentage of males making rivalry songs (%) |
|---|---|---|
| Males exposed to GLY | 76.5 | 19.5 |
| Males not exposed (control) | 89.5 | 4.5 |
There were 850850850 males in the control population. Each male made only one type of song.
Use this information and Table 1 to calculate the number of males making courtship songs in the control population.
Suggest one change the scientists could make to both cricket populations to increase the number of male courtship songs.
The scientists also investigated the effect on female response times of exposing male bush-crickets to GLY. Table 2 shows their results.
Table 2
| Population | Median duration of female courtship response (s) |
|---|---|
| Males exposed to GLY | 14 |
| Males not exposed (control) | 35 |
Glyphosate-based herbicides (GLY) are widely used in agriculture and can contaminate wild grassland habitats through drift or direct application.
Suggest and explain the effect that GLY contamination in wild bush-cricket habitats will have on bush-cricket reproduction. Use information from Table 1 and Table 2 in your answer.
