Thesprotia graminis (Grass mantis)


This rather long and slender mantis is found throughout the southern US all the way to Mexico. They have a very tiny head and very skinny legs. The males are excellent fliers and can hover for long periods of time. Their catching arms are rather small compared to other mantid species. When threatened, they’ll stretch out their arm to mimic a stick..


Males grow a little bit over 2 inches long while females grow to 2.5-3 inches. After the 3rd molt, 8 segments can be counted on the male’s abdomen while 6 on the females. Adult have long visible antennas while the females sport tiny ones. Females are also wingless and can be difficult to tell if they’re matured.


This species of mantis relatively resistant to all kinds of conditions since it was found in a fairly hot and humid area, although it is best to keep them in a moderately warm atmosphere. Keep these at 30 C (86 F). Keep their humidity maintained at around 50-60%.


Their cage should be well ventilated. They’re rather long for their size and will need some space to crawl around. The general rule for caging is 3x the mantis’ length for the height and 2x for the width and length dimensions. This species will spend most of its time hanging upside down so plenty of perches will be necessary. They are not an aggressive species and can be housed together.


This species eats very tiny prey. Adults will readily feed on large fruit flies and small moths, but because their catching arms are so tiny, the flies or moths must fit inside its arms. They are capable of hunting for themselves so no hand feeding is required. Feed them as much as it will eat in one day and do not feed it for another 2 days. Watch their abdomen, if it is fairly inflated, then stop feeding them. As for watering, mist nymphs lightly every other day and two to three times a week for adults.


A mantis will stop eating a few days prior to its molt. Mantises molt about every 1.5-2 weeks as babies and the time in between each molt increases as they get older…so their last molt into adulthood can sometimes take as long as 3 weeks. It takes about 7 molts for females and about 6 for males. During molting, it is vital that you do not disturb them and also make sure that the humidity is at a safe level…the suggested level is fine. The mantis will hang upside down from a branch or the screen lid and will sometimes shake or spasm violently. Then after a while, it worms out of its old skin and will hang out to dry. Once it’s dried, it will resume eating and being its normal self. Note that height is very important since they are quite long and need the extra space.


This species is very easy to breed due to its docile nature. After 2 weeks since their last molt, introduce the female into the male’s enclosure near him. A mature male will respond quickly. It could take hours before the male does anything though. He will jump on her back and grab her thorax. After a while of holding on (this could take from hours to days), the male will bend his abdomen down to connect with hers and mating will commence. Once they are finished, the male will fly away and must be removed to reduce any chances of cannibalism.


After two weeks or so, the females will be depositing her oothecae. This species can deposit from 10 to 15 oothecae, each every 4 or so days. After 3 weeks of incubation at 30 C (86 F) and 70% humidity, about 15-20 nymphs will hatch out from each one. These can be reared together for easy feeding. Then they can be removed after a while if need be. These can be fed on fruit flies a day or two after hatching. Then continue to care for them as this care sheet suggests.

Additional Notes: my wildcaught female has lain 6 oothecae in captivity (1 before mating and 5 after mating). Each was lain exactly 4 days after another. The oothecae are very small and are about half a cm. The turn slightly reddish a couple days after being deposited.
The female is very aggressive. She’ll tackle small crickets that look almost too big for her small hands, but she’ll hold on to them and promptly eats them slowly.
The nymphs hatch out very small and at first, I was afraid that they couldn’t eat fruit flies…but the nymphs managed to catch the flies alright. They molt their first molt about 1 week after hatching and their 2nd molt came in about 9 days or so.