Life cycle of Mantis Species from Resaca de la Palma State Parks
(Part 5)
2.4        Ootheca hatching

S. carolina oothecae have always hatched in the morning, usually between 7 a.m. and 9 a.m. Hatching might be triggered by the
morning light, to provide the newly hatched mantids with a better opportunity for locating hiding spots, while dispersing away from the
ootheca.

As mantises do not undergo a full metamorphosis process, hatchlings resemble miniature versions of adult mantises, except that
they are smaller and without wings. During the wingless stages, they are called nymphs.

Adult females usually deposited the ootheca so that the ootheca seam faced outward (or downward), thus allowing the hatchlings to
emerge without any obstructions. Hatching started with a few grub-like nymphs wiggling out from the seam. Apparently, a passage
way directly connecting the egg chamber to the seam exists. The first few nymphs that wriggled out of the ootheca appeared to trigger
a mass exodus, where fleets of grub-like nymphs hatched simultaneously, forming a large gathering of wriggling nymphs dangling by
threads.
Figure 2.4-1: S. carolina ootheca hatching
The S. carolina nymphs emerged from the seam head first (see Figure 2.4-1) where two prominently, black eyes were very distinctive.
The nymphs then proceeded to wriggle out of the ootheca, by a bodily twisting motion, with great effort. That seemed to be a critical
stage because nymphs could be trapped in the process trying to free itself from the ootheca.

Soon after the nymph was freed from the ootheca, the grub-like nymphs, which were still enclosed in membranous sacs, dropped out
of the ootheca and hung in mid-air by a silken thread connected to the rear of the abdomen. This was obviously another crucial step in
hatching process, as gravity provided the legless nymphs with the required space to break free from the bag-like membrane or sac
that enveloped the nymphs throughout their entire incubating process. Eventually, each nymph broke entirely free from their sac by
outwardly extending its appendages (see Figure 2.4-2) while simultaneously expanding its abdomen, leaving only the membranous
shred behind to hang near the seam of the ootheca (see Figure 2.4-2).
Figure 2.4-2: Ootheca threads
Usually, not every developed mantis egg inside the ootheca was able to hatch out successfully. Nymphs could become trapped,
unable to break the membrane enclosure, while trying to emerge from the ootheca. Some nymphs managed to free their bodies from
their membranes, but were hindered by a thread on one of the legs. There were also some that died in-situ while in the ootheca,
probably because they were too weak to emerge through the seam. These unfortunately nymphs possessed inferior genetic traits,
which ensured that only the genetically strongest survived the first ‘task’ of hatching. In the wild, only a very small proportion of the
robust and fortunate nymphs continue to mature into adults by successfully obtaining proper nutrition, and more importantly, evading
such predators as birds, lizards, spiders or even its own species including other mantids.

The entire hatching process usually occurred over a half hour period. All hatchlings appeared pale and yellowish in color within the first
hour of hatching (see Figure 2.4-3), but eventually transformed into a green/brown color after twenty-four hours (see Figure 2.4-4).
Figure 2.4-3: Newly hatched S. carolina nymph
Figure 2.4-4: A day old S. carolina nymph next
to the ootheca
Generally, newly hatched nymphs immediately moved away from the ootheca. Some climbed upwards using their threads to return to
their ootheca, while others dove to the bottom of the cage. A few continued to remain near the ootheca for a brief period before
dispersing to escape detection. All hatchlings were lively and actively seeking new places to explore.

The hatching pattern was considered the “all out bursting” type, where most, if not all nymphs hatched out within a quarter of an hour.
The ootheca was left undisturbed for a few days after hatching, but no further emerging nymphs were observed.

Based on Table 2.3-2, the number of hatchlings ranged from a minimum of 28 nymphs to a maximum of 55 nymphs. The only
exception was the last ootheca deposited by SF1, which yielded only 8 nymphs. Ootheca SO4b was distinctly small and deformed; it
was the last ootheca deposited by the adult female, SF4. It was common to find the last few oothecae hatch out very few, if any nymphs
at all.
Figure 2.4-5: SO4b ootheca
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To be continue - Part 6