Life cycle of Mantis Species from Resaca de la Palma State Parks
(Part 9)
Although 1RS3 took the least time to mature, it was the largest among the three selected captive bred specimens. The total number of
days required to achieve the adult stage for both 1RS1 and 1RS4 were 96 days, while it only took 1RS3 87 days to mature.
Figure 2.5-26: Molts from 1st instar to 8th instar (adult) for female S. carolina
2.6        Cannibalism

General

All mantids are carnivorous and in S. carolina, cannibalism is a common occurrence especially when food and space are limited.
Cannibalism has been observed to occur as early as the second day after hatching. The aggressor usually launches an attack on the
head of the victim by using its raptorial front legs, which explains why many cannibalized victims are decapitated. Sometimes, the
victim manages to escape by violently moving its body to shrug off the aggressor’s death grip and thus, releasing itself from being
eaten. Size difference is also an important component of cannibalism. Mantids usually avoid prey that appear too large to handle, but
will chase after smaller prey, including their own kind, when ravenous.

Cannibalism occasionally occurs during mating, where the adult female seizes the adult male’s head and feeds on it while the adult
male continues copulation (see Figure 2.6-1). The headless and sometimes, prothorax-less male will continue to copulate with the
female for 24-48 hours before falling to the wayside, or in most cases, being entirely consumed by the female.
Figure 2.6-1: Cannibalism during mating (S. carolina)
Some adult males could fall victim to cannibalism even before mating with the female, mainly due to the disadvantage of the males’
diminutive size. Due to this inherent tendency of the females, the adult males remain cautious when approaching potential mates.

Selected specimens
The selected five nymphs for growth study were kept in individual containers to prevent cannibalism. However, the adult females were
mated by adult males from the group rearing, and cannibalism was observed in one of the pairings.

Group specimens
For the batch that was kept together in a net cage, cannibalism occurred particularly when food supply was scarce. The earliest signs
of cannibalism were observed upon finding the surprise hatching of SOx when one of the hatchlings was discovered headless. It had
obviously been eaten by a sibling (see Figure 2.6-2).
Figure 2.6-2: Cannibalism at 1st instar
This species was not very aggressive in the early nymphal stages. But as they grew, the smaller nymphs fell prey to the larger ones on
several occasions, sometimes even when food was plentiful. Some mantids molted sooner than others and therefore with their size
advantage, cannibalized smaller nymphs. Also, it was observed that the female S. carolina was more robust than the male. With the
size discrepancy, the diminutively sized male usually became food for the female when housed together in a net cage.

Cannibalism also occurred during molting. Molting mantids were defenseless against attacks from their own species. The wriggling
movements during molting attracted the attention of the nearby mantis, making the molting mantis more vulnerable as prey.

During captivity, several net cages were prepared to house different group of mantids. Ultimately, most of the surviving mantids were
the larger sized females. Only a few males that hid among the leaves survived to the adult stage. Assuming an equal gender ratio for
each hatching, the female biased group at the end, demonstrated that many males fell victim to cannibalism if both genders were kept
together. In order to avoid the females from completely obliterating the male population, a separate cage was prepared to house only
the subadult males. The separation of cages based on gender helped to reduce the rate of cannibalism. There were no further deaths
due to cannibalism in the males’ cage after the separation; however, occasionally cannibalism continued to occur among the female
group, although sufficient feeders were provided continuously for both gender cages.
Figure 2.6-3: Headless S. carolina male nymphs due to cannibalism
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To be continue - Part 10