Mexican Free-tailed Bats

The other night we took a friend to see the Mexican Free-tailed Bats at the Congress Street Bridge here in Austin, Texas. This is the largest urban bat colony in the world. It had been a while since I had seen it and reminded me of the great photo opportunities I've had with this species.


The Mexican Free-tailed or sometimes called Brazillian Free-tailed Bat (Tadarida brasiliensis) is a wide-ranging bat found throughout North, Central and South America. They get their name because of their long, prominent tail.


They can roost in a number of different places from buildings to trees, but they are probably best known for the large colonies they form in caves. The photo above was taken at the Eckert James River Bat cave owned by the Nature Conservancy. It is one of the largest bat nursuries in North America and his home to around 4 million bats throughout the summer. The emergences from this cave are quite impressive.




The two photos above were taken at Bracken Cave owned by Bat Conservation International. It is home to the largest bat colony in the world and is home to some 20 million Mexican Free-tailed bats that emerge every night throughout the summer. It is truly a spectacular phenomenon and I encourage anyone  who has the opportunity to watch an emergence. They are so numerous when coming out of the cave that as they fly in a cyclone like pattern up and out of the entrance, some bats get pushed to the outside and are actually impaled on prickly pear cactus spines!

The Dark of Night

Blacklighting, or the use of an ultraviolet light to attract insects at night is a favorite past time of almost every entomologist. This technique can bring in amazing numbers of insects. The most productive time to blacklight is usually on a calm, balmy night with a new moon and no competing artificial light sources. It is fun to take the time to photograph insects coming into these lights. Because they are nocturnal, many of these are seldom seen.


This is a composite of many moths, beetles, true bugs, caddisflies, and true flies that came to a light I had setup throughout the night.


This Armyworm moth visited the light frequently one night. The larvae can be very destructive on a variety of crops and considered serious pests.


This is not a mosquito, but rather a non-biting midge in the family Chironomidae. They are really neat when seen up close. Like mosquitoes, their larvae are aquatic, but as their name implies, they cannot bite and are harmless.


This is the adult of a net-spinning caddisfly in the family Hydropsychidae. This group of insects have aquatic larvae. The adults look like moths, but they have hairs on their wings rather than scales and they lack the coiled proboscis found in moths and butterflies.


This caddisfly belongs in the family Leptoceridae. They are called Long-horned caddisflies because they have very long antennae.


This is one of my favorite insects, the dobsonfly. The larvae are aquatic, called helgramites, and are often used for fish bait. The adults are short-lived, secretive and thus rarely seen by the casual observer. Males (left) in this group have very long sickle-shaped mandibles that they use to grab a hold of the female (right) with during mating. They are large and really cool looking!

Scorpionflies Everywhere

I look forward to seeing scorpionflies every fall, but this year they were particularly abundant here in Austin. I was able to escape the lab and photograph both males and females in flight and perching. It was interesting to watch as males defended and fought over a dead grasshopper. They would release pheromones that in turn attracted females.

Bats, Bats and more Bats

Kendra and I had the opportunity to join Liz Braun de Torrez from Boston University this last Saturday night. Liz is working on her Ph.D. and focussing on bats that are feeding on insects in Pecan groves. We had fun photographing four different species, Red Bat, Cave Myotis, Evening Bat, and Eastern Pipistrelle. Here is an example of each bat.

Phorid (Scuttle) Flies

These flies belong to a large family called Phoridae or Scuttle Flies. They are parasites on many different invertebrates. These photos are of two species (Pseudacteon obtusus and P. tricupsis) attacks the Red Imported Fire Ant (Solenopsis invicta). They quickly lay an egg in the thorax of the ant, then the larva hatches and migrates to the head of the ant where it eats out the head capsule, which eventually falls off!