The bella moth also demonstrates complex mating strategies and is thus an excellent model to study sexual selection.

Females mate multiply and receive spermatophores containing sperm, nutrients and alkaloid compounds from numerous males as nuptial gifts.

Utetheisa ornatrix is found from southeastern United States to South America (southeast Brazil).

[1] This species is found to be more common in more tropical parts of this range, in accordance to the availability of its host plant in more southern regions.

[4] The eggs of the Utetheisa ornatrix are spherical in shape and range in colour from white to yellow to sometimes brown.

[6] These plants contain large amounts of toxins, particularly pyrrolizidine alkaloids (PAs), which are found in high concentrations in the seeds.

Since PAs are an extremely valuable resource, individual larvae compete with one another to colonize an entire pod, an elongated seed-containing pouch from the food plant.

[7] Larvae that are unable to take ownership of a pod must obtain the chemicals from leaves, where they are found at much lower densities.

[6] PAs render the bella moth unpalatable to many of its natural enemies like spiders and insectivorous bats.

[10] In contrast, bella moth individuals grown on a PA-free diet are readily preyed on by spiders.

[11] It has been experimentally shown that bella moth larvae upregulate the expression of this gene when the amount of PAs in their diet increases.

[12] This is more common since feeding on one single larva is sufficient to compensate for the cannibalistic caterpillar's alkaloid deficiency.

[15] Bella moths of both sexes use very complex reproductive strategies, making this species an excellent model system for studying sexual selection.

[7] They mate with an average of three to four males, each of whom provides her with a nuptial gift, a spermatophore containing sperm, nutrients, and alkaloids.

[7] Adult males invest up to 11% of their body mass to create a spermatophore they provide to a female during mating.

[17] Since spermatophores contain nuptial gifts of pyrrolizidine alkaloid (PA) and nutrients, multiple mating helps the female increase the fitness of her offspring.

[20] They emit these chemicals in short pulses to provide close-range orientation cues to male moths as they seek out the females.

[25] Due to the unequal mating rates, males become valuable to females and female-to-female competition rises dramatically as a consequence.

[16] Females of this species do not select based on age, mating order, between-mating interval, or duration of copulation.

[27] Selecting for these males provides the females with multiple benefits such as obtaining sperm packages with more defensive pyrrolizidine alkaloids which results in larger offspring.

[20] For example, males that fed inside a seed pod rather than on leaves produce higher levels of HD.

[16] Females direct a postcopulatory selective process where they choose male sperm based on the intensity of the courtship pheromone that was released prior to copulation, hydroxydanaidal (HD).

[7] The intensity of this signal is directly proportional to the amount of alkaloids sequestered by the moth during the larval stages.

[7] As a consequence, this pheromone is an indirect indicator of success during larval development and will ultimately determine which sperm will be passed on to the offspring.

[29] The alkaloid is stored during the larval stages and retained through metamorphosis, protecting both larvae and adults from predators.

[30] Another problem that females face is the risk of incurring a PA deficit due to the large amount of eggs they lay.

[1] The word Crotalaria originates from the Greek root “crotal,” which means “a rattle” and is characteristic of the pods found on these plants.

[1] Specific host plants used include: Pyrrolizidine alkaloids (PAs) are the toxins the bella moth is able to ingest and use for protection from predators.