Aussie Stick Hatchlings

Lots of critters are hatching around Pacific Science Center including eggs from the Australian stick (Extatosoma tiaratum) insect colony. This week, Animal Care Intern Davis presents another educational video on the behind-the-scenes rearing of these Phasmatodae.


Watch this: https://youtu.be/_D6RZapG_xA

We check the stick insects every day to see if any nymphs have emerged from their eggs. Every three or four days we mist the eggs with water to keep the humidity high enough for the stick insects to emerge. If we find a baby stick insect, we make a notation on the board, transfer it into a little container, and then transport it to the exhibit to be with the rest of its family!

For more information about parthenogenesis and the life cycle of these fascinating insects, read our recent article: Captain Phasmatodea and the Attack of the (Not Really) Clones.

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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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Seattle Bug Safari

Seattle Bug Safari, the wonderful arthropod museum located in Pike Place Market, recently closed their doors. Because of the closure, their fantastic variety of exhibit animals needed to find new homes.

Many of the species exhibited are animals regulated and could only go to permitted owners. Fortunately, Pacific Science Center holds those permits. So last month, Animal Caretakers Sarah, Chris, and Lauren went on an adventure to pick up some new arthropods for Animal Care.

We loaded up on boxes and containers to hold our new friends, hopped on the monorail, and headed down to Pike Place. When we got there, owner Brian Rolf brought us in to look over the selection. We knew we had to fight the “kid in a candy store” syndrome; mainly take creatures that we already exhibit and/or have the space and resources for. With that in mind, we packed up the following:

1 Chilean Rose Tarantula
9 Blue Death-feigning Beetles
4 Diving Beetles
4 Cactus Longhorn Beetles
6 Giant Brazilian Cockroaches
57 Australian Prickly Sticks

Most of the animals joined others of their species on exhibit. Australian Prickly Sticks, a species we have had in the past, are now on display. In addition to the Prickly Stick adults and juveniles on exhibit, we have numerous containers of their eggs hatching in an off-exhibit nursery. The young Prickly Sticks can grow up in the quiet of the back room with lots of blackberry leaves to enjoy. After a few molts, they will be placed on display.

Thanks to Brian and Seattle Bug Safari for some amazing new animals! Watch Brian showing his knowledge and insect handling skills here: http://www.king5.com/new-day-northwest/Seattle-Bug-Safari-Invades-the-New-Day-Northwest-Studio-89542582.html. Do you recognize some of the arthropods we also have at Pacific Science Center? Come by and visit them!

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Stick Insect Babies

Australian prickly stick insects (Extatosoma tiaratum) are a mainstay of Pacific Science Center’s Insect Village. They live just over a year, so to have continuous insects, we rear them through their whole life cycle.


Each year, we incubate and hatch out eggs. As they grow, the stick insects will shed five times in the process of becoming adults. They will then mate and lay eggs, which we collect and hatch out, to start the cycle again.

This year, the last of the adults was starting to age before the first of their eggs hatched. We did not want a gap in our population, and started looking for some new recruits to fill the gap. Martin Feather of the San Antonio Zoo came to the rescue. He had plenty of 2nd instar (developmental or growth stage) stick bugs, more than he could use. After confirming that they were allowed on our USDA (United States Department of Agriculture) permit, he packed them up and sent them over.

These new youngsters arrived with some of their host plant material. They had been eating eucalyptus, but appear to be transitioning to wax myrtle without complaint. Come see them next time you visit.

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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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