The influence of sex on feeding behaviour in Pacific white shrimp (Litopenaeus vannamei)

The Pacific white shrimp (Litopenaeus vannamei) is the most cultivated species in crustacean aquaculture and a potentially important consideration for its production could be the use of monosex cultures. Generally, female penaeid shrimp are larger than males due to a greater gain in mass per moult cycle, resulting in a clear size dimorphism in adults. It is unknown whether this dimorphism is driven by differences in feeding behaviours between male and female L. vannamei, which may be important in deciding whether or not to use monosex cultures. Here adult L. vannamei (n = 20; 26.02 ± 0.66 g) were identified by sex (n = 10 per sex) and allocated to separate tanks for individual recognition. Following 24 h feed-deprivation, individuals were introduced to test arenas along with feed provided ad libitum. Shrimp were recorded for 20 minutes in the test arena, and this was repeated once per day, for five consecutive days. Several sets of behaviours were analysed in relation to feeding, and tracking of individuals across repeated measures allowed behavioural variation both within- and between-individuals to be monitored. Results revealed several behavioural differences between males and females. Females were generally less active than males, while males spent more time detecting feed and feeding. In general, males were bolder than females, arriving more quickly to the feeding tray and there was less individual variation in male feeding activity. These clear differences in feeding behaviour between female and male L. vannamei support growth advantages in females as a result of better food utilisation and require consideration for future use of monosex cultures.