Sunday, February 28, 2010

The Disperser Morph

This goes in the “just when you think you’ve seen everything” category.

One morning as Animal Caretaker Maida Ingalls prepared for her day, the early shift custodian pointed out to her that one of the naked mole-rats had escaped. This occasionally happens. A mole-rat will get out of the system of tubes and chambers, and wander aimlessly around the interior of their enclosure.

In this case, something much more dramatic had happened. The animal was spotted on the ground in front of the exhibit.

Maida quickly put him back and briefly recorded the escapee information. At first she couldn’t figure out how he got on the floor, but was able to deduce that he must have crawled between the doors and the sill, and then slid down the signs in front of the exhibit. Quite a feat for such a small animal! Surely the experience would dampen his enthusiasm for travel!

Not quite. Two days later, the same individual performed the same escape. This time there was a difference. While in his first escape, he had pushed one of the tubes out of a chamber, this time there was no visible means of escape. We did notice that one of the latrine chambers was filled especially high with bedding, almost to the very top of it. We believe he must have climbed the bedding and pushed the lid open to crawl out. So we taped down all of the chamber lids, hoping to prevent another escape. The offending mole-rat was marked with a black pen on the leg and observed for signs of trauma, then returned to the colony.

Only to escape yet again! During a cleaning later in the week, a new latrine chamber was installed without tape on the lid. Our perceptive mole-rat figured this out, filled the chamber with bedding and climbed out the top one more time. This time, when he reached the ground level, he climbed through a ventilation damper into the area below the exhibit, which could have been extremely dangerous if we hadn’t found him soon after. What was this hairless Houdini up to? Did he have a death wish?

Interestingly enough, this behavior has been described in other colonies as well, and it doesn’t appear to be entirely suicidal. This mole-rat is presumed to be a disperser morph – an individual within a eusocial group that is driven to carry its genetic material out of the colony of origin and found a new colony or integrate into an existing one. In the stable, well fed colonies kept in captivity, the disperser is usually a male, but in the wild males and females seem to become dispersers in about equal numbers.

The disperser might be thought of as a high risk, high reward behavior. The chances of survival in the wild for a solo mole-rat are slim. But any disperser hardy enough to stay alive and lucky enough to attract a partner is far more likely to produce offspring than he or she would be by remaining at home as a worker. To an animal living in an established colony, the pathways to breeding involve fighting – either with an established breeding animal, or with other contenders if the queen or her mate die. As founder of a new colony, the disperser would have ample opportunity to produce his or her own offspring rather than caring for those of others.

If our Houdini is a disperser mole-rat, his behavior is powerfully motivated and may continue. We are testing husbandry techniques to see whether high levels of enrichment will meet his dispersing need. If he is isolated from the colony, will he work to get back in? Or is getting away the whole point? Eventually, he may need to become a founder of his own, or join another organization’s colony, perhaps as a breeder. In the mean time, this peculiar behavior offers us yet another glimpse into the many adaptations of this eccentric species.

Read more!

Friday, February 26, 2010

Fresh Sheet - February 26, 2010

“Fresh Sheet” is our weekly shipment report of pupae on display in the emerging window. Visit Pacific Science Center’s Tropical Butterfly House and meet our newest residents.

Costa Rica

10 - Caligo eurilochus (Forest Giant Owl)
10 - Caligo memnon (Owl Butterfly)
03 - Catonephele mexicana(Mexican Catone)
78 - Catonephele numilia (Numilia)
14 - Chlosyne janais (Crimson Patch)
59 - Colobura dirce (Mosaic butterfly)
11 - Consul fabius (Tiger Leafwing)
40 - Danaus plexippus (The Monarch)
56 - Dryas iulia (Julia Longwing)
08 - Hamadryas amphinome (Red Calico)
10 - Heliconius doris (Doris Longwing)
10 - Heliconius sapho(Sapho Longwing)
05 - Heliconius sara(Sara Longwing)
15 - Heraclides anchisiades (Ruby-spotted Swallowtail)
35 - Hypna clytemnestra(Silver-studded Leafwing)
18 - Mechanitis polymnia(Polymnia Tigerwing)
35 - Morpho peleides(Blue Morpho)
46 - Nessaea aglaura(Aglaura Olivewing)
65 - Papilio thoas (Thoas Swallowtail)
02 - Parides arcas(Arcas Cattleheart)
15 - Philaethria dido(Scarce Bamboo Page)
09 - Phoebis sennae (Cloudless Sulphur)
25 - Tithorea tarricina(Cream-Spotted Clearwing)

Total = 625

Read more!

Tuesday, February 23, 2010

Butterfly Detective

There are many tasks that the Life Sciences department does for the Tropical Butterfly House behind public view. As mentioned in a previous post about pupae pinning, every week we document the numbers of butterflies that are shipped. These are noted in our weekly “Fresh Sheets.” However, one of the more daunting tasks is to identify and record all of those butterflies that don’t successfully emerge to live out their lives in our garden.

As the emerging process is perhaps the most difficult part of a butterfly’s life cycle, not every pupa turns into a healthy and capable butterfly. Some pupae never emerge. Others emerge the wrong way, damaging their wings so they’re unable to fly. Also, we monitor any pupa that have been affected by fungus or parasitoids. It’s important that we record individuals that don’t emerge properly so that we are reimbursed by our suppliers. This information helps them to improve the way butterflies are farmed.

The identification of dead butterflies can be a difficult and tedious job. Our department carries several butterfly encyclopedias and vendor guides to help us with the process. By using visual identification and a process of elimination we are able to identify the specie's country of origin for each individual butterfly. We currently have five active suppliers from which we receive hundreds of pupae every week. In 2009 alone, we received 132 different species of butterflies. You can imagine that for someone with little practice at identification, identifying partially emerged butterflies can be a very long process.

So what do we look for when we identify dead butterflies? The color patterns and designs on the wings are the first identifying marker. You can look at a butterfly’s open wing colors or their closed wing colors. The shape of the butterfly also helps in identifying species. Swallowtails have a tail-like design similar to a fork tail on swallows. Another example is the Longwing butterflies, which have a much longer forewing than hind wing. Measuring wingspan length and body size can also mark a species.

But there are still some obvious challenges. Many butterflies have multiple similarities in design and color. If the wings are in poor condition, this can often make the identification process difficult. When the wings are too damaged we search the thorax and abdomen for identifying markers. Some of the more difficult characteristics can really throw you for a loop. Some species are dimorphic, which means male and female look different. There are many types of butterflies that can also display mimicry, which is defined by a similarity in appearance between two species that protects one or both of those species. Markings can also be regional for a species. It is common for the same species of butterfly to have a series of different designs depending on the different geographic regions of origin.

From an outsider’s viewpoint, it may not seem like a critical task but in actuality it is crucial to the operation of our butterfly exhibit. This data determines which species have the best emergence rates. That information can influence which species and from which vendors we will purchase from in the future. Most importantly, this data collection allows us to become transparent as a department in Pacific Science Center, as well as an organization answerable to the United States Department of Agriculture (USDA). And as our skill in tracking problems with pupae improves, we learn best practices to reduce these very loses. In other words, by knowing what has gone wrong, we are better able to keep butterflies healthy and keep the exhibit looking good.

Therefore, accuracy of this task is important to the future success of the butterfly house. Personally I’ve had moderate success at identifying dead butterflies, but I have noticed that some people have a natural knack for the process. Even though it’s difficult for me, I try to work through this task every week so that eventually I can learn to identify most species with relative ease. So go ahead. Quiz me.

-Adrian Eng, Animal Caretaker & Butterfly Detective

Read more!

Friday, February 19, 2010

Fresh Sheet – February 19, 2010

“Fresh Sheet” is our weekly shipment report of pupae on display in the emerging window. Visit Pacific Science Center’s Tropical Butterfly House and meet our newest residents.

El Salvador

30 – Battus belus (Belus Swallowtail)
30 - Caligo memnon (Owl Butterfly)
30 - Catonephele numilia (Numilia)
20 - Consul fabius (Tiger Leafwing)
20 - Heliconius erato(Small Postman)
25 - Heliconius hecale(Tiger Longwing)
15 - Heliconius hortense(Mountain Longwing)
08 - Heliconius ismenius(Ismenius Longwing)
10 - Lycorea cleobaea (Large Tiger)
75 - Morpho peleides(Blue Morpho)
20 - Myselia cyaniris (Blue Wave Butterfly)
30 - Myscelia ethusa (Royal Blue Butterfly)
15 - Prepona omphale=archeoprepona omphale (Blue Belly-Button)
10 - Siderone nemesis (Red-striped Leafwing)
10 - Tithorea harmonia (Harmonia Tigerwing)

Total = 348


40 - Battus polydamas (Polydamus Swallowtail)
40 - Heraclides anchisiades (Ruby-spotted Swallowtail)
20 - Heliconius erato(Small Postman)
33 - Heliconius melpomene(Postman)
05 - Heliconius hecale(Tiger Longwing)
40 - Dryas iulia (Julia Longwing)
10 - Catonephele orites (Orange-banded shoemaker)
10 - Anartia amathea (Scarlet Peacock)
22 - Biblis hyperia (Red Rim)
40 - Caligo memnon (Owl Butterfly)
10 - Mechanitis polymnia(Polymnia Tigerwing)
10 - Tithorea harmonia (Harmonia Tigerwing)
20 - Phoebis sennae (Cloudless Sulphur)

Total = 300

Read more!

Wednesday, February 17, 2010

Fit For a Queen

Over the course of the night on Tuesday, February 9th, Elphaba- one of our two “queen” naked mole-rats, gave birth to a surprisingly large litter of pups. When we came in on Wednesday morning, we found 22 brand new babies in the colony.

The size of the litter surprised those of us on the Animal Care team because it was more than twice the size of her largest previous litter. She also just didn’t look like she had that many pups inside her when she was pregnant. In fact, she looked relatively trim. Whereas Galinda (the other “queen”) often looks like she’s swallowed a couple of golf balls by the end of her pregnancies, Elphaba has generally remained smaller, and this pregnancy was no exception. It may go without saying that all of the babies born in this litter were very undersized.

The pups were born into a completely sterile environment, as we had just completed day 14 of our “superclean” the previous day. The older colony members seemed to do very well with the babies, taking care of them when necessary and not being too rough with them as they ran around the enclosure. Still, none of this was enough for these pups. By the end of day on Saturday, they had all passed away. None of them made it to that crucial day 5.

So why didn’t they make it? It seems there’s always something, with our naked mole-rats. This time we believe it was the sheer size of the litter. There were simply too many pups, and they were all too small for any of them to have a fighting chance.

As I explain the problems with this litter to visitors and staff, I can’t help but be reminded of one of the basic theories of animal ecology and reproductive strategy. Famously, ecologists Robert MacArthur and E.O. Wilson developed the theory of r/K selection based on their studies of island ecosystems. According to this theory, the processes of evolution push all animal species towards two main reproductive strategies, K-selection or r-selection. K-selected species have relatively few offspring, into which they invest a lot of time and energy, so that most of those offspring are likely to survive. Conversely, r-selected species have many offspring (think millions), into which they invest little time or energy, so that few of their offspring are likely to survive. There is a trade-off, essentially: Quality versus quantity. Do you want to spend more energy making babies or raising babies?

How naked mole-rats fit into this theory is a little confusing, but that’s to be expected from this eccentric species. As mammals, they and their ancestors have been pushed towards K-selection for millennia. That’s why mammals give live birth and nurse our young. For mammals, it is evolutionarily risky to have too many offspring, simply because most mammalian biological systems are not designed for many babies. At some point mammals can no longer provide the care that the offspring need to survive.

Naked mole-rats have the largest litter size of any mammal — up to 28 pups in a litter. But when litters are this large, usually few or none survive. And unlike real r-selected species, naked mole-rats don’t reproduce quickly enough to make up for this low survival rate. Their gestation period is still at about three months. In these instances they are behaving like neither r-selected nor K-selected species. They are in an evolutionary no-man’s land, which is not positive for the growth of our own mini-mole-rat population. So why have such large litters? What is the evolutionary benefit here?

For most animals, reproducing is about more than just spreading your genes around, at least in the short term. When an animal is able to produce successful and healthy offspring, they are also making a statement to their peers. They are proving their fitness, attracting better mates, and in some species, actually improving their social standing. In a naked mole-rat colony, especially one where two queens are competing for dominance of the colony, a female that gives birth to 22 babies may prove herself to be more “queen-like” than one who only produces 10.

And so the saga continues. Although it’s sad and frustrating that another litter was lost, this may just be a blip in a truly epic battle. Elphaba has proven that she can have just as many babies as Galinda (two more, even!). The gauntlet has been thrown. What will happen next? What can happen next? We will know more in just a few more weeks. Galinda is pregnant, and predicted to give birth in the mid-March. We will, of course, keep you posted.

Brianna Todd, Lead Animal Caretaker

Read more!

Friday, February 12, 2010

Fresh Sheet - February 12, 2010

“Fresh Sheet” is our weekly shipment report of pupae on display in the emerging window. Visit Pacific Science Center’s Tropical Butterfly House and meet our newest residents.


30 - Cethosia biblis (Red Lacewing)
16 - Doleschalia bisaltide (Autumn Leaf)
30 -Graphium agamemnon (Tailed Jay)
50 - Hypolimnas bolina (Great Eggfly)
100 -Idea leuconoe (Paper Kite)
18 - Pachliopta kotzeboea (Pink Rose)
100 - Papilio lowii (Sunset Swallowtail)
30 -Papilio palinurus (Banded Peacock)
20 -Papilio polytes (Polite Swallowtail)
99 - Papilio rumanzovia (Crimson Swallowtail)
45 - Parthenos sylvia philppensis (The Clipper)

Total = 538

Read more!

Tuesday, February 9, 2010

Solution for an Itchy Problem

As noted in our recent article on the veterinarians’ visit to Animal Care, we were given some recommendations on how to break a virus cycle that may be causing health issues in our naked mole-rat colony.

While doing the super-clean process for the naked mole-rats, Animal Care staff observed an extremely distressing behavior. Individuals in the colony were itching frantically. Some of the mole rats would pause as they passed certain points in the enclosure, scratch their sides with their hind feet, and move on.

Others were even more profoundly affected. One or two animals seemed to itch everywhere and were nearly immobilized in their efforts to relieve their discomfort.

Now while it is not uncommon for mole-rats to show some self-grooming behavior during cage cleaning, these activities usually subside within ten minutes of chamber cleaning. But in this case, some animals showed no signs of settling down.

Because we were using a new, more aggressive disinfectant, our first thought was that some residue had not been rinsed off. The chambers were removed, cleaned with a mild, non-irritating detergent, rinsed and quickly replaced. All of this was done with an eye on getting the animals comfortable as quickly as possible. It worked – immediately as new chambers were put in, the scratching stopped.

All of the tubes and chambers for the following day’s change-out were subjected to the same double cleaning process; no residual disinfectant could possibly remain. Yet once again, the itching began.

Something else must be going on – but what? A clue came while cleaning up a dirty chamber. Minute particles of bedding stuck to the Plexiglas walls. The process of cleaning and towel drying the chambers had created static electricity, which was irritating the mole-rats! When the chambers were replaced the day before, they were still damp from cleaning, and therefore non-irritating!

Problem solved! We no longer towel dry our chambers. We let them air dry. Furthermore, we lightly dampen them before use to eliminate any static that might remain. The mole-rats are happier, and we can rest assured that our efforts to help them don’t create a new set of problems.

Read more!

Friday, February 5, 2010

Fresh Sheet - February 5, 2010

“Fresh Sheet” is our weekly shipment report of pupae on display in the emerging window. Visit Pacific Science Center’s Tropical Butterfly House and meet our newest residents.

El Salvador

30 - Battus belus (Belus Swallowtail)
35 - Caligo memnon (Owl Butterfly)
40 - Catonephele numilia (Numilia)
30 - Consul fabius (Tiger Leafwing)
10 - Heliconius erato(Small Postman)
20 - Heliconius hecale(Tiger Longwing)
75 - Morpho peleides(Blue Morpho)
25 - Myscelia ethusa (Royal Blue Butterfly)
10 - Papilio pilumnus (Three-tailed Swallowtail)
40 - Prepona omphale=archeoprepona omphale (Blue Belly-Button)
10 - Siderone nemesis (Red-striped Leafwing)

Total = 325

Los Angeles

10 - Ariadne Ariadne (Angled Castor)
10 - Athyma perius(Common Sergeant)
10 - Catopsilia scylla(Orange Emigrant)
10 - Cethosia biblis (Red Lacewing)
10 - Charaxes brutus (White-barred Charaxes)
20 - Chilasa clytia(Common Mime)
10 - Danaus genutia(Common Tiger)
08 - Doleschalia bisaltide (Autumn Leaf)
10 - Euploea core(Common Crow)
10 - Graphium agamemnon (Tailed Jay)
10 - Hypolimnas bolina (Great Eggfly)
30 - Idea leuconoe (Paper Kite)
10 - Ideopsis juventa(Wood Nymph)
10 - Kallima inachus (Dead Leaf)
10 - Papilio constantinus (Constantines's Swallowtail)
10 - Papilio dardanus (Mocker Swallowtail)
10 - Papilio demodocus (Orchard Swallowtail)
10 - Papilio helenus (Red Helen)
10 - Papilio lowii (Sunset Swallowtail)
10 - Papilio memnon (Great Mormon)
10 - Papilio nireus (Blue-banded Swallowtail)
10 - Papilio ophidicephalus (Emperor Swallowtail)
10 - Papilio palinurus (Banded Peacock)
10 - Papilio polytes (Polite Swallowtail)
10 - Papilio rumanzovia (Crimson Swallowtail)
10 - Parthenos sylvia lilacinus (Blue Clipper)
10 - Parthenos sylvia philppensis (The Clipper)

Total = 298

Read more!

Tuesday, February 2, 2010

January Vet Visit

On Jan 19, Dr. Maas and Dr. Temple from Avian and Exotic Animal Hospital paid a routine house call to Pacific Science Center’s animals.

Each of our snakes received a full physical exam from head to tail. The insides of their mouths were examined for broken teeth, pale gums, excess saliva, or loud breathing. The skin was inspected as well. Snake skin should be clear and unblemished, without old scales from previous skin sheds.

Snake’s undersides were felt for lumps or irregularities. Overall conditions were noted. Estella is a little heavy! Dr. Maas recommended we feed each of the boa constrictors a small rat on a weekly schedule.

It was in this exam that a strange lump was felt in Maizey, the corn snake’s abdomen. As previously explained, Dr. Maas took Maizey back to his hospital for further examination with sad results.

Lydia, the leopard gecko, looks great. She has a fat tail which is a sign of good health in these animals. We were warned to not associate her with other leopard geckos as they might not be as healthy.

Dr. Maas recommended that we house our African dwarf frogs separate from the axolotls. Their skin is toxic to axolotls. The frogs are currently partitioned from the axolotls with a simple tank divider. Should a frog escape and end up in an axolotl mouth, it could be fatal to both animals. Stay tuned! Plans for a separate dwarf frog exhibit are in the works!

The naked mole-rats were looked at for overall colony health. Most of them have gained weight over the last year. Pups from our two recent litters are nearly the size of the smallest adults. Unfortunately, a few individuals are not thriving. We discussed how best to monitor them, and set up a plan for a thorough colony clean. In future articles, we’ll discuss our naked mole-rat husbandry routines and report on the results.

All in all, the vets’ visit was careful, thorough, and exhaustive. Animal Care staff always learns a lot from these house calls which help us better care for our animals.

Thanks to Alice Enevoldsen, Pacific Science Center’s planetarium specialist, for photographing the veterinarians’ visit.
Read more!