Stick Insect Amnesty

By Sarah Moore

Do you have some stick insects or walking stick bugs that you inherited from a classroom, or got as a pet, and that you don’t want any more? Did you know that Pacific Science Center has permission from the United States Department of Agriculture (USDA) to accept any non-native stick insects?


The USDA fears that there are many non-native stick bugs that have the potential to become naturalized and harmful pests. We encourage stick bug owners to retire their colonies by bringing them to us. If they are able to escape into the outdoors, these insects are invasive and have the potential to severely harm the environment. Many species of stick insect are parthenogenic, meaning capable of reproducing without males. In other words, eggs from females are viable without being fertilized. So in addition to careful containment of the insect, all their bedding must be destroyed – ideally by freezing. (Do not compost!)

In some states, the USDA has dealt with colonies of these insects being released into new habitats and becoming established. We want to make sure that Seattle and its environs don’t have this happen. We will cheerfully accept any stick insects that are brought to us.

If you would like to bring us your stick insects, please contact us at feedback@pacsci.org. We will make arrangements for you to bring them in to the Science Center.
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Captain Phasmatodea and the Attack of the (Not Really) Clones

Star Wars excitement just won’t seem to quit for our Life Sciences Team. Several of us have commented that the Imperial Storm Troopers seem to come in two flavors: clone and not-clone. Simple. But for the Phasmatodae, it’s complicated.

Phasmatodea is the group of insects that include all the stick insects. Here at Pacific Science Center you can see three representatives, Medauroidea extradentata and Lonchodiodes samarensis (Vietnamese and Samar stick insects) and Extatosoma tiaratum (Australian prickly sticks).

Some species of stick insects can reproduce without males, a process called parthenogenesis. Our Vietnamese stick insect population has not produced a male in years.

This is a fast way for a female to make her own “clone army”, producing large numbers of offspring without the risks and lost energy of seeking a mate. For an insect with an abundant food source, this lets her colonize it faster. So why do some of their near relatives go through the entire mating thing?

It turns out that the stick insects’ process is little more complex and varied than creating identical clones as single cells do (or sea anemones). The female doesn’t make duplicates of herself, but instead generates a bit of diversity by creating eggs with different combinations of her own chromosomes. Like shuffling the same cards again and again, she will produce many combinations. As long as the combinations fit the environment, this is a speedy and efficient system.

But there is no room for new genes to be introduced. Over time, species that become parthenogenic become less and less able to mate and get locked into their reproductive pattern. When the environment changes, it may be harder for these species to adapt, as they have a smaller group of genes to draw on. Under such circumstances, a similar species that reproduced sexually might prevail.

Again, it’s complicated.

For the in depth story please see the following articles:

http://phasmid-study-group.org/sites/phasmid-study-group.org/files/More1996.pdf

http://link.springer.com/article/10.1007%2FBF00328476

http://rspb.royalsocietypublishing.org/content/280/1764/20130823.abstract


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A Stick Bug Mystery

When Animal Care recently received a shipment of stick insects identified as Baculum extradentatum, (Giant Vietnamese stick insects), we naturally assumed that would be what we were getting. We were planning on adding this shipment of walking sticks to our current population to add in some genetic diversity and hopefully a few males to our all-female parthenogenic group.

As soon as we unpacked this new group of phasmids, it was clear that they were not the same as our current population. Perhaps we were looking at males instead of all the females we are accustomed to. But soon we realized that there were more differences. We were looking at a new species.

When we receive a new species of stick insect, we don’t simply slap a new sign onto a cage. These animals have the potential to become as invasive as the Indian stick insects in California. We first needed to figure out what species these insects were and then make sure we had a permit for them – fast! Otherwise, we wouldn’t be able to keep the new shipment.

Thanks to the powers of the Internet, Lead Animal Caretaker Lauren Bloomenthal contacted phasmid authority, Paul Brock, of London’s Natural History Museum. With full body photographs and a couple of shots of the insect’s head and genitalia, the expert soon replied with a name: Lonchodiodes samarensis. Their common name is Colorful Samar walking stick and "colorful" they are!

Unfortunately, even though we had a name, this species still wasn’t on our permits, so their fate was still up in the air. Life Sciences Manager Sarah Moore contacted our officer with the United States Department of Agriculture and explained our situation, fearing that nothing could be done to keep these animals. But he wrote back to say that the USDA would add the phasmids to our permit. We could keep and display these beautiful stick insects! Perhaps our excellent record of care worked in our favor to make this possible.

Lonchodiodes samarensis are now on display in the Insect Village. They are originally native to the Northern Province of the Island of Samar in the Philippines. Very little information is known about this species but we look forward to learning more about them as we see them grow and thrive in their new home.


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Stick Bug Feeding

During the 11 years since the opening of the Ackerly Family Gallery, Pacific Science Center has maintained exhibits of Australian Prickly Sticks (Extatosoma tiaratum) and Vietnamese Stick Insects (Baculum extradentatum). They are visually and behaviorally interesting and have been very popular with the public.



For most of that time we have fed both on blackberries (Rubus spp.). Blackberries have the advantage of growing locally year round, making them relatively easy to obtain. Not surprisingly, however, they are not too popular with the staff taking care of the stick bugs. Aside from the obvious problem of thorns, they have a tendency to wilt rather quickly which requires changing out the feeding material in the cages weekly.


A short while ago, we learned that a colleague in another institution was having some success feeding his Australian Sticks Wax Myrtle (Myica californica). This shrub, like the blackberries, has the advantage of growing year round in the northwest and Pacific Science Center has the advantage of having a good deal of it in the plantings on our grounds. In addition, it seems to have a longer “shelf life” on exhibit so it doesn’t need to be changed out as often. Best of all – NO THORNS!!


We decided to give it a try. The Australian Sticks took to it like a duck to water. We have now successfully reared them from egg to adult and seen eggs from insects raised on the new diet.


But, the Vietnamese Sticks did not seem to care for it nearly as much. They would nibble on the myrtle but did not seem to be thriving. To meet their dietary preferences and maintain some of the advantages of the myrtle, we now dress the Vietnamese Stick Insect cage with a large bunch of myrtle, for appearance, and place a smaller bunch of blackberries in a container behind it where it is easily accessible from the cage opening. This way, we can change out the blackberry branches more often while leaving the myrtle in place until it begins to look wilted which generally is much longer that the blackberries. In addition to its good looks, the myrtle provides ample climbing surfaces so that younger stick insects can spread out without risk of thorns.


Bottom line, happy stick bugs and happy caretakers!

-Dan Warner, Animal Caretaker
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Stick Bug Amnesty Redux

In June, the Life Sciences Department announced that the United States Department of Agriculture is allowing us to accept any non-native stick insects as an incentive for schools, pet stores, and private citizens to retire their colonies. So far, we've had a couple of responses to our appeal.


This is a reminder that, in the wild, these insects are invasive and have the potential to severely harm the environment. Remember: Vietnamese Stick insects are parthenogenic. In other words, eggs from females are viable without being fertilized – not an uncommon occurrence in insects. In addition to being careful with containment of the insect, any bedding must be destroyed. This means incineration or freezing. (Do not compost!)

Please contact us at feedback@pacsci.org if you have any questions or would like to participate in our Stick Bug Amnesty Program.


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Stick Bug Amnesty

One of the thrills for visitors to Pacific Science Center's Insect Village is the opportunity to handle some of our arthropods. In the past, our United States Department of Agriculture (USDA) permit allowed us to let visitors hold the Madagascar Hissing Cockroaches, African Giant Millipedes or Vietnamese Stick Insects in a controlled setting. Unfortunately, the conditions of our USDA permit have changed recently and the Vietnamese Sticks will no longer be available for public handling.

According to Life Sciences Manager, Sarah Moore this is not really bad news from a containment point of view. Vietnamese Stick insects are parthenogenic. This means eggs from females are viable without being fertilized – not an uncommon occurrence in insects. It has been a long held concern of the USDA. What if a Vietnamese Stick dropped an egg into someone’s clothing?

The USDA fears that there are many non-native stick bugs out in public schools, pet stores, and private homes that have the potential to become naturalized and harmful pests. We encourage these owners to retire their colonies. As an incentive, the USDA has given the Life Sciences Department permission to accept any stick bugs from the public. Please contact us at feedback@pacsci.org if you would like to participate in our Stick Bug Amnesty Program.

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