Can Stick Insects really mate for 1400 hours?

I saw this tweet a while back, and it made me awfully curious:

Is that true? Because that seems like not a very smart thing to do, if you are a large and tasty insect.  Or, in this case, two large leaf-eating insects belonging to a group that specializes in being invisible to predators by looking like a stick.  Two sticks having sex is the sort of thing I’d notice, anyway.

The risk of predation while you are making out–or more literally “hooking up” in the case of insects–is a major issue.  You can see from this photo that a fair amount of Kama Sutra-ish contortion is needed to successfully maneuver into place.  This does tend to inhibit one’s ability to run away!

Several different papers I read repeated that stick insects have remained paired for up to 79 days, but I was not able to see an actual reference with the original details.  Some of the references cited date back to 1910, so not surprising that I can’t get my hands on a digital copy.

From one paper describing mating behavior:

“The Indian stick insect Necroscia sparaxes may remain coupled for up to 79 days (a record for insects)”…Intromission may occur only initially or intermittently. In either case, a substantial proportion of male time-investment is not spent in ejaculate transfer. 

In captivity, Diapheromera veliei and D. covilleae pair for 3 to 136 hours and the penis may be inserted and removed up to 9 times. The genitalia are not in contact for ca. 40% of this period, and attachment is maintained by a male clasping organ.

It’s generally thought that the male hangs around in order to have repeated matings, but also to drive off other males that want to get lucky. I found several reports of stick insect menage a trois (or sept) in the literature, including this etching of kinky stick insect activity.  The male is–literally–cock-blocking a competitor.

So, it’s probably correct to say that stick insects can remain paired for up to 79 days, even though I can’t verify that directly. It is less correct to say that they “have sex” for 79 days, just as it would not be technically correct to say you mated for 8 hours if you had sex at 10pm and again at 6am.  Well, unless you are into that tantric stuff, anyway.

Snce 1400 hours = 58 days, the numbers don’t match up, and it is not correct that stick insects mate for 1400 hours.   It’s more like 1,896 hours!

References:

Sivinski, J. (1978). Intrasexual Aggression in the Stick Insects Diapheromera Veliei and D. Covilleae and Sexual Dimorphism in the Phasmatodea, Psyche: A Journal of Entomology, 85 (4) 405. DOI: 10.1155/1978/35784