Aleochara bilineata, commonly known as Rove Beetles, are known both as parasitoids and predators to certain populations. In fact they play a large role in the population stabilization of some pests, especiallPicture of a white maggoty Delia radicum, commonly known as cabbage root maggots or flies (Royer & Boivin 1999). These cabbage root maggots play an important role in the reproduction of the beetles.  The cabbage maggot’s eggs are needed for a host to the A. bilineata larvae, and the cabbage maggot’s larvae are needed as a food source to adult A. bilineata (Gauvin 1998).

Rove beetle females do not lay their eggs in or on the host, but instead they lay them in the soil that is likely to harbor hosts. Each A. bilineata female can produce approximately nine to 15 eggs per day or 700 eggs in its lifetime (Broatch et al. 2008). The oval-shaped egg is a milky white color after the female lays it. It varies between 0.38-0.50 mm. After the egg is laid, it will take three to 19 days for the larva to emerge. Hatching occurs fast; between five and ten seconds (Gauvin 1998). The larvae must search for a host first thing after hatching. They have to search through the soil to find a pupa to consume and live in. Once they find one (that is not already taken over by line drawing of a larva beetlelarva) they chew their way inside. They settle in the space between the puparium and the nymph. Then the beetle larva closes the entrance hole by secreting a sticky substance through the anus which serves as a plug (Lize et al. 2010).

After the entrance hole is closed, the larva will begin to eat the nymph. The entire host pupa is consumed (Lize et al. 2010). A. bilineata larvae are not able to live outside the host puparium for very long. If a larva doesn’t find a host in six to eight days it will usually just die off (Gauvin 1998).  Sometimes two or more larva will enter the same puparium, but only one will live to maturity.  A. bilineata pupates within the host in late fall, spins its cocoon, and will emerge as an adult when winter is over. That is where they spend the winter (Shelton 2013). Adult rove beetles will live 40-72 days (average 46), so normally the cycle will happen two times per year. The first generation of adults would be born in early June, the second in August/September (Gauvin 1998).
Rove beetles perform internal fertilization in order to fertilize female rove beetles eggs. Like most internally fertilizing insects, during reproduction the male and female will perform sexual intercourse and the male willPicture of a black rove beetle deposit spermatophore into the female’s spermatheca. (Green 2002). “The male bends its abdomen over its head and its claspers and aedeagus are extruded. The copulation (sexual intercourse) lasts between 20 and 65 seconds” (Gauvin 1998).  Female  A. bilineata normally mate many times. They are at sexual maturity the moment they break out of the puparium. Sometimes they will even mate before they find something to feed on (Lize et al. 2009). 

Female A. bilineata do not participate in courtship nor do they show parental care to their offspring (Lize et al. 2009). They also do not have any specific breeding periods. They are able to mate their entire lifetime. The whole 46 days of it. It is necessary to mate multiple times in order for the female’s eggs to be properly fertilized. Their eggs are sterile when produced- mating is required to start oogenesis (the maturation of a female’s eggs). Oogenesis will start 36-72 hours after mating for the first time (Lize et al. 2009).

An experiment was done by Lize, Cortesero, Poinsot, and Boivin, scientists from Canada working on studies about the Biology of Organisms and Populations applied to Plant Protection, specifically the sperm storage by female A. bilineata. This study concluded that the more sperm the female can hold, the more fertile she will be throughout her life. Mating frequently will ensure the fertility of the eggs throughout the female’s life. Unfortunatly, there is a cost. Female longevity decreases when females mate at regular intervals.  So although it will decrease her life span; her eggs will have a better chance at producing viable offspring, so overall it is beneficial for the female to mate multiple during her lifetime (Lize et al. 2009)

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