Saturday, April 27, 2013

The other Spider Wasp

When I think of spider wasps, usually the big Tarantula Hawk (Pepsis or Hemipepsis) comes to mind first. They are the most impressive members of the family Pompilidae or Spider Wasps. Huge, colorful, rating three out  of four on Justin O. Schmitd's pain index scale ...and we have many more species of the same family here in Arizona. I am finally learning to recognize them by their sturdy shape and the spurs on their hind tibiae, even when they are not dragging their name-giving prey around.

When caught and stung, the spider is paralyzed by the wasp's venom. The adult wasp will not feed from its prey but store it in a hole, dug by the wasp or often even by the spider itself if she was ground-dwelling. The solitary wasp will lay one egg on the spider and over time the wasp larva will develop, slowly eating the paralyzed spider alive. The wasp larva will then pupate and later emerge from the burrow as an adult.

Most primitive Hymenoptera follow this pattern. Provisioning the larvae with a nectar/pollen mix as practised by bees and some wasps is considered a phylogenetically higher development, as is the cooperative raising of the brood by several or many related females in the social wasp, bee and ant species.
Isodontia elegans with a katidid
 Like the Pompilidae, wasp in the family Sphecidae (Thread-wasted Wasps) also provision their brood with paralyzed prey. Every species in this family targets its own very narrow range of  prey species. In an earlier blog I have described the two closely related Chlorion spp., the Steel-blue Cricket Hunter and the Cyaneus Roach Hunter that are easier to identify by their prey preferences than by their looks. 

Ammophila sp., I imagine that the long abdomen serves as a counter-weight for the long-bodied caterpillars that the members of this genus have to transport

 As a family Sphecides (Thread-waisted Wasps) can be easily recognized by the extremely elongate and thin waste, or petiolate abdomen, that all member-species have in common. It provides the wasp with the flexibilty to bring the stinger at the end of the abdomen forward to sting the prey insect that she is holding with her long legs.

While some Sphecids like Ammophila build rather simple ground nests that they close by pushing sand over the opening with their foreheads, others, like Isodontia (Gass Carrier Wasps)  close the entrance with a plug of specially collected grass cuttings. 

Other family members build far more elaborate structures. Last winter, Randy and our friend Frank watched a wasp flying repeatedly into the water heater cabinet on the side of Frank's house. When they finally told me, the wasp was gone but a cluster of mud cylinders, one of them still open,  was attached to a waterline. To my relief it was the line that feeds the swamp cooler, so the young wasps were in no danger of being cooked alive when Lyn and Frank were taking a hot shower.
I kept visiting the nest ever now and then, planning to eventually wrap it in gauze to catch at least one of the inhabitants.
From December to March nothing happened. 

 In mid April (yesterday), there was suddenly a second hole in the clump of hardened mud, and something seemed to be going on in the cylinder that was always open. When a slender black and yellow wasps suddenly emerged I wasn't prepared and only got a very blurry photo before he disappeared. By now I sensed that things would quickly begin to happen in the other chambers, too, so I removed the whole nest carefully and brought it home (to our bedroom where the light is best).

Black and Yellow Mud Dauber, Sceliphron caementarium, emerging

 I heard buzzing from at least two chambers. I now see that I positioned the nest up-side down, that may have aggravated the kids. The noise made me wonder: to buzz like that, they must be already clad in a well-hardened exoskeleton. No wonder Number One had made such a fast exit. But now I was ready.
Soon moist spots appeared where two cylinders were plugged with concrete-hard mud. Next a pair of mandibles pushed through and cut out a circular area which then fell outward. The head showed, the front legs, and seconds later the whole wasp emerged: A  Black and Yellow Mud Dauber,
Sceliphron caementarium.This one took off right away, too.

The next one allowed me to get my little camera ready for a short birthday video with sound:

Here is a link to the flickr version of the same video. I think the quality there is somewhat better than the blogger-direct-upload and not as cluttered as u-tube

Empty exuvia left in the chamber, spider leg top left side

 Removing the sidewall from the now empty chambers I found the empty, parchment like pupal exuvia and a single spider leg. A female Black and Yellow Mud Dauber catches spiders of many different species to stock the nursery before she lays one egg in each cylinder.  There is another, related Mud Dauber that preys mainly on Black Widow Spiders. Our healthy young wasps had finished all their provisions before they pupated.

 Here are 2 pupae that I removed before they hatched but that turned into adults later

  I am very grateful to Gary R. McClellan for allowing me to use his images of a Black and Yellow Mud Dauber nest that he opened before the wasp larvae had eaten the spiders. The photos clearly show the variaty of spider species in the wasp nest.

Prey assembled in the nest of Sceliphron caementarium (Black and Yellow Mud Dauber) Photos by Gary R McClellan

Sceliphron caementarium


Atkins versus High Glucose diet:
While the growing larvae needed to build up their bodies and hence lived on a high protein diet, adult Mud Daubers need fast burning calories for their high energy flight muscles. Their live now centers on finding a partner, building a mud house, and hunting. To support this lifestyle they are nectaring on flowers, especially on those easily accessable ones of the parsley and carrot type (Umbelifera). For lack of any wildflowers I offered Lantana to our kids, but they didn't like it at all and buzzed off. There are always our hummingbird feeders...

P.S. The first time I saw a Mud Dauber actually collecting mud I was watching dragonflies at a pond on Fort Huachuca. That was when it was still open to aliens like me. Here at home in the very dry bajada of the Tucson Mountains, I had never seen any wasps of that genus. But some years ago, Frank put in a bird bath that is always overflowing and creates a little mud puddle while also feeding one of his huge mesquite trees. The wasp found this mud source and began building her nest not far from a porch light that attracts hundreds of moths and consequently spiders at night. In the morning I often still find spiders hanging around. They need to watch out! 7 new Daubers are on the prowl and they tend to establish nests in the same place where they hatched.

Sceliphron caementarium

 Hymenoptera (Ants, Bees, Wasps and Sawflies) » Aculeata - Bees, Ants, and Stinging Wasps » Apoid Wasps (Apoidea)- traditional Sphecidae » Sphecidae (Thread-waisted Wasps) » Sceliphrinae » Sceliphrini » Sceliphron » Sceliphron caementarium (Black and Yellow Mud Dauber)

Wednesday, April 24, 2013

Insects at Sabino Canyon

Bush Katydid, Scudderia sp., nymph,

Leaf Beetle, Griburius montezuma
Metallic Wood Boring Beetle, Acmaeodera griffithi
Broad-nose Weevil, Ophryastes sordidus
Mesquite Longhorn Beetle, Aethecerinus latecinctus
Ironcross Beetle Tegrodera aloga

 Blister Beetle, Nemognath sp.
Mating Treehoppers, Vanduzea laeta

Friday, April 19, 2013

It always pays to watch the competition

Yesterday, when I arrived for the weekly nature walk of the Friends of Sabino Canyon the temperature was in the fifties. Much too cold for mid-April morning in Tucson and too cold for most insects and lizards that I wanted to see. In addition, a fierce wind was howling down into the canyon from the Catalinas. The other naturalists decided to look mostly at plants, I guess because those can't hide from the elements. Two saguaros, one with an imposing crest, looked indeed positively defiant.

Eastern Collared Lizard, who stayed hidden yesterday (Photo Ned Harris, April 2012)
But I don't get to Sabino often enough, so I was going to give Esperero Trail a try because that's where I had seen the beautiful Eastern Collared Lizards last year. The trail leaves the main canyon and winds up the mountain side with full exposure to the western wind gusts. It seemed like a dumb idea but I am stubborn and in Arizona the sun usually breaks through eventually.

View into Sabino Canyon from Esperero Trail
 Well, it didn't and there seemed to be very few living things willing to share the exposed mountain side with me. Until I came to some part of the trail that rose somewhat over its surroundings resulting in a low but pronounced hill top.

Ash-throated Flycatcher, who was out and about
 There was a big Ash-throated Flycatcher busily swooping from his perch as if catching - flies? Sure enough, even in this abysmal weather some Bee Flies, Tachinids, Robber Flies  and even some butterflies (Tiny Checker Spots, Marine Blues) were hill-topping, a behavior that is typical for many flying day active insects.

Some of the hill-topping flies and butterflies
 Males had staked out little territories, patrolling back and forth, chasing everything that flew by, driving off other males and trying to mate with passing females. I think I understand why the big collared lizards and the flycatcher seem to prefer this exact area. It's the place where they can be sure to find enough prey. Of course the ectotherm lizards had the luxury to take the cold day off while the endotherm bird had to keep working, especially as he was feeding nestlings that I could hear keening in a Saguaro hole. I followed the bird to an especially exposed area with some bare boulders where he seemed to concentrate his efforts.

 At first I payed little attention to a big black fly that landed as if to bask in one of the sparse sunny spots because I mistook it for a Mexican Cactus Fly, a common syrphid. But then I heard a very deep basso buzz when the fly changed to another boulder, only about 5 m from the first. That sound is one of the loudest and deepest flight noises I've ever heard here in Arizona - not easy to forget. Through my new little Papillon binoculars I could also verify that the fly was not all black but had silvery grey flanks - a bot fly in the genus Cuterebra. (Later identified by Jeff Boettner as C. austeni)

Rodent Bot Fly, Cuterebra austeni, Esperero Trail, Sabino Canyon, Pima County Arizona, April 2013 
This is only the third time that I encountered these big, fascinating insects. Some people may feel that the live history of bot flies seems like an episode from the X Files or the movie Aliens. I think, however, that the film makers borrowed their ideas from the biology of these flies whose larvae are mammalian parasites.

Deer Bot Fly, Cephenemyia jellisoni infects the alimentary tract of ungulates like white-tailed deer, mule deer, moose or elk. Photo by Philip Kline Pusch Peak,  Catalina Mountains, Pima County, Arizona, March 2009
 While some bot fly larvae develop in the alimentary tract of mammals, the big black and grey Cuterebra that I was watching yesterday belonged to the group that develops subcutaneously in mammals. Luckily they are quite species specific in their host choices so I knew that I wasn't the target - the host would most likely be a rabbit or a pack rat.

Pack rat with 2 nearly grown Cuterebra larvae Photo Jan Emmings
 The female fly will lay hundreds of eggs in rat runways. Only a few of the larvae will actually find their way into a passing rodent.There it will develop rather quickly feeding on the body fluids of the rat that this irritation draws. Inflammation and pain are controlled by the larva and the wound heals very quickly as soon as the guest drops out of the host to pupate.

Cuterebra sp. larva ready to pupate found crossing Sabino Canyon Rd. on Feb. 22, 2011. Photo by Fred Heath

Rodent Bot Fly, Cuterebra sp., Pima Canyon, Catalina Mts. Pima County, Arizona, September 2009
 The only bot flies likely to infest humans do not occur north of Southern Mexico. As I mentioned, the deep characteristic buzz of the big flies is rather recognizable and would probably warn the victim of an intended egg drop. To give their larva a chance to find their way into the body of a wary primate, female bot flies in the genus  Dermatobia  have an amazing strategy. They capture another insect like a mosquito, horsefly or tick that is drawn to warm blooded mammals for its own reasons and attach a load of their eggs to this carrier. When the released  mosquito later lands on a primate for a blood meal, the bot fly eggs hatch and the young larvae bore into the warm skin of the doubly victimized monkey or human.

 While feeding from the host subcutaneously for several weeks the larvae have to behave reasonably well. They seem to prevent inflammation even though they need to keep a hole in the host's skin open to be able to breath periodically. They probably have anti inflammatory and antibiotic capacities. I have two good friends who both got parasitized in Central America, are now in their eighties, and live and love to tell about it. If not removed prematurely, the larvae will eventually leave the host, drop to the ground and pupate. In time a new generation of mature adults will hatch. These big flies are born without mouth parts. From their time as maggots in the flesh, they are provisioned with enough energy reserves to survive for about 10 days, time enough to start the cycle again.

Catching the redeye to Amhesrt, MA 
Yesterday's bot fly, however, is not going to propagate his genes this way. Instead he is contributing them to conservation biologist Jeff Boettner's research project at UMASS - Amherst. There are many open questions concerning host relationships and phylogeny of the group. As specimens are difficult to obtain, Jeff would be grateful for specimens and info about lek sites. Here is a link to his info pamphlet.
Here is a link to photos of the removal of a human bot fly larva (Peruvian Amazon)
Arthropoda (Arthropods) » Insecta (Insects) » Diptera (Flies) » Calyptratae » Oestroidea » Oestridae (Bot Flies) » Cuterebrinae (New World Skin Bot Flies) » Cuterebra (Rodent and Lagomorph Bot Flies)

Tuesday, April 16, 2013

Velvet Mites, Trombidioidea and Chiggers

With this post I am going out on a limb. I got an e mail request to identify a small red bug. I am using bug here as a general term for arthropod, because:

'Hello Dr. Brummermann,
My co-worker and I were on Mt Lemmon today, in the Marshall Gulch area and we came across thousands of tiny red insects. Our first thought was chiggers, but after looking into it, these insects were too big to be chiggers.
They were bright red, had 6 legs, and large antennae. About 25% of the ones I looked at appeared to be dead (curled in on themselves and dry), but this could have just been the case for the one location that I was seriously investigating them in.
While I don't have any pictures, I can guess they were approximately the size of this "o" (San Serif, 12pt font). They were found in areas with large amounts of dead leaves, and when we dug under the leaves, they appeared to be moving through the soil.
Do you have any ideas as to what we saw?'

Without a photo there is not too much to go on. What seemed to be dead ones could be exuviae - in that case I would guess that they were some early instar true bugs or other hemipterans. But since they seemed to be soil related and bright red, how about mites instead of insects? Their front legs could be mistaken for antennae. Here is a photo of a giant velvet mite:
They are usually bigger than your 'o' but.... There are often outbreaks with thousands of them. They are predators as adults.
Let me know what you think and consider carrying a camera for documentation!

Trombidiidae (Velvet Mites) from my backyard. These live in sandy soils, are huge, around 5 mm in length and show up only after rains

Thank you very much for the speedy reply!
They could have been mites; we didn't have any magnifying lenses on us at the time, so I could have mistaken the front legs for large antennae. Will they bite humans (or other large mammals) or do they only go after other insects? If I'm up in the area again within the next few weeks, I'll take a picture!
Thank you again,

At first, I was going to say
Your observation that the bugs were in the leaf litter makes me think that they are really in the family Velvet Mites (Trombidiidae) and not the so called 'Red Spiders", also mites, that live and feed on plants and can become pests.
Velvet Mites (Trombidiidae) may be parasitic on insects as young instars. As adults they will become predators of insects. This is the info in BugGuide, Wikipedia and other web locations.

But I am now looking at John Henry Comstock's 1948 Spider Book, revised in 1965 by W.J. Gertsch. I know that is ancient for a science book, but while a good part of the older taxonomy had to be  revised according to more recent phylogenetic research, the life history of the described organisms has not changed and the old biologists were famously thorough observers.

This last paragraph sounds suspiciously like chiggers, doesn't it?

I moved on to the 1998 Review: Biology and Ecology of trombiid mites (Acari: Trombidioidea) by Zhi-Qiang Zhang, Experimental and Applied Acarology, 22 (1998). The paper first states that the systematics of the group are in flux, and many of the old subfamilies that Comstock still included have since been accorded family status.

Euryopis sp. Spider with a trombidioid larvae (red) and trombidioid adult on the left
 These mites are of economic importance and may be used for biological pest control. But identification even to the genus can be difficult and in many cases either the larval stages and hosts are not known or the larvae are described but not the adults. Trombidiid larvae have been found as parasites on many different arthropds. Some seem very host specific, others can use a variaty of hosts.

If you can read this table that I copied out of the Zhang paper, you'll find that two of the families do use vertebrates as their larval hosts: Leeuvenhokiidae and Trombiculidae They are Chiggers!
So the chiggers that chew into the vertebrate skin (not burrow under the skin) are larvae of Velvet Mites, but not all Velvet Mites are chiggers. Here is a link to the blog of Dragonfly Woman where she explains how the young chiggers actually feed on vertebrate skin.
The mites I was asked about are probably not chiggers, for two reasons: First, It is far too early and cold for chiggers on Mt Lemmon right now. We still had snow a couple of weeks ago.  Second, chiggers (the parasitic larvae) are very tiny, much smaller than the observed mites. But I cannot tell whether these mites could be the adults of what we call chiggers.

Arthropoda (Arthropods) » Arachnida (Arachnids) » Acari (Mites and Ticks) » Acariformes » Trombidiformes » Prostigmata » Anystina » Parasitengona » Trombidiina » Trombidioidea » Trombidiidae (Velvet Mites)

Tuesday, April 9, 2013

A Giant Crab Spider becomes a Gigantic Crabspider

Our friend Frank planted an Olive Tree in his backyard in Picture Rocks, Arizona. Then, being in the plumbing trade, he staked it with copper tubing. A Giant Crab Spider, Olios giganteus, moved into the copper pipe, but kept hiding from my camera.

I kept trying. Then one night, Randy and I found the spider hanging upside down, hog-tied by its own thread. What was going on? I'd never seen this species spinning any silk before. Then I noticed: Its carapax looked funny as if the tegment (dorsal part) had come loose like the lid of a can.

The side view was clearer: the spider was molting. The transparent grey part is the emerging spider in its new skin. Like insects, spiders have stiff  chitinous exoskeletons that cover at least the thorax and the extremities. Muscles attach to the inside, sensory hairs sit on the outside, The cuticula even  gives structure to tracheas and lungs, and it forms sharp claws and scelicera. But it is rigid when fully hardened and needs to be shed periodically for the spider to grow.    

A new pair of new chelicera appeared under the old ones (darker) and also a new row of eyes
Controlled by hormones, a complete new skin is formed under the old one. This includes sensory hairs, claws, even the lenses of the eyes. Molting fluid separates the two layers. The old carapax opens at certain seams, and, like a butterfly escaping the chrysalis, the hanging spider uses gravity's force to pull out of the old skin. It has to happen this way because the new skin is still so soft that the spider's muscles have nothing to work against and are useless.

The abdomen has torn loose from its very thin old skin
 The abdomen of spiders is never covered in a hardened exoskeleton. This part of the body often shrinks or expands depending on the spiders hydration or nourishment status, or when the female is pregnant. But the abdominal skin is also included in the molt, maybe so the spider emerges with a fully renewed set of sensory hairs that cover the entire body. 

The spider in it new pale skin is hanging under the old exuviae, with most of the length of the legs still inside

Suddenly the palps fall forward one by one and their swollen distal parts reveal that this is now a mature a male. He will fill the blueish genital bulbs with seminal fluid from his abdomen. Then he will keep the sperm in his palps until he finds a female that allows him after elaborate courtship to  transfer a spermatophore into her spermatheca. Male palps and female epigyna (cover and opening of the spermatheca) differ greatly from spcies to species and allow sex only among members of the same species.
 If you look closely, you can see the exuvia of the old palps just above the old chelicerae, and there were no genital bulbs. This means that this guy just went through puberty with this molt!

I was watching the progress of the molt now for more than 15 minutes (I carry no watch, but Randy had long left for home because he is not THAT interested in bugs and he can always look at my photos later)....
The spider was now wiggling slightly and rotating on its silk thread because his center of gravity began to shift when his long legs pulled free.

After he had pulled completely free from his exuvia, the spider stayed suspended from his silk line. All extremities were extended. The new skin now needed to harden and dry to become a functional exoskeleton, pigmentation would mature, and I had reached the end of my camera's battery life.

Exuvia and freshly molted spider (hanging still under and attached to the old skin)

I wanted to come back in the morning to claim the exuvia. I was hoping to see how a spider's complex book lungs are represented in the old cuticula. But in the morning there was no trace left of the night's miracle. I did meet Mr. Giant Crab Spider sitting proudly on his copper pipe though.

female Giant Crab Spider Olios giganteus Photo by R. Hardy copyright
Since he was again shy of having his portrait taken, I am showing instead Randy Hardy's spectacular photo of a female Giant Crab Spider. For scale, the scarab beetle (Cyclocephala melanocephala) in her fangs is about 10 mm long (little less than a half inch). Next to her huge black chelicerae her palps are visible,which in females look just like a pair of short extra legs.

Arthropods (Arthropoda) » Arachnids (Arachnida) » Spiders (Araneae) » True Spiders (Araneomorphae) » Entelegynes » Giant Crab Spiders (Sparassidae) » Olios » Olios giganteus 

Wednesday, April 3, 2013

Promachella pilosa, a new genus and species for BugGuide and the UAIC

Every morning during breakfast on the patio we sneeze at all the pollen that drift over from blooming Creosote and Brittle Bushes. We both have been in Arizona long enough to develop pollen allergies. While Randy so far just sneezes, I experience the whole spectrum from itchy eyes to sinus problems. But eventually I will jump up with my camera that sits always next to my coffee cup to get even closer to the flowers (I very much appreciate that my point and shoot camera has no view finder. While this seemed to be a serious draw-back at first, it now saves me from getting my face right into the blooming bushes.)
Most of the insects are arriving to either collect pollen and/or nectar, find mates, eat parts of the flowers or leafy parts or deposit their eggs so their off-spring can do so. A few spread their eggs so their off-spring can hitch rides on other flower visitors to  become a parasitic guest in their nurseries.
And of course this aggregation of spring insects also draws some predators.

Promachella pilosa female
 Yesterday I observed a robberfly that was feeding on a small bee. She was busy and easy to approach so I got some good photos. In shape and coloring she reminded of the genus Promachus, but at less than 15 mm she seemed small.

Promachella pilosa male
 Not much later I found a similar, but even smaller male. He was shyer and kept landing among the branches of a Creosote bush, so his portrait didn't turn out quite as well.
On BugGuide Dr. Eric M. Fisher a Diptera specialist with special interest in Asilidae identified
my patio robbers as Promachella pilosa. I am rather proud to say that this added a new Genus and species to Bugguide. Checking the online species data base of the UAIC, I found that there are no (identified) specimens in the collection either.
While it is nice to photograph something new and special (I found no other photos on the web) there is not much information out there either. I have no access right now to Willcox original 1937 paper. So all I know so far is that this is a fly that is only known from Arizona and from neighboring Sonora, Mexico. 
But since the appearance is so similar to that of the widespread genus Promachus, and the female is lacking the dagger-like ovipositor of some genera that stick their eggs into plant material, I guess that the females of the genus Promachella deposit their eggs into the soil.