Saturday, July 21, 2012

National Moth Week - not much going on in AZ, or is it?

At the end of July, National Moth Week is coming up. It's a first for the US and many organizations like for example Bugguide are sponsoring it. While 'Lep' experts in most states offer many special 'mothing' events to the public, Arizona seems to be sadly lagging behind: One event in the Grand Canyon area but nothing in our famously biodivers  SE corner of the state. I think I know why we have ignored repeated suggestions to organize and sponsor an event: We are too busy, too busy mothing, that is.

On my camera after black lighting at the garage wall at our house in Picture Rocks Arizona in early June
 Iam no Lepidopterist. I was originally much more interested in beetles, but this year I have been following the appearance of moths species at our house, documenting over  80  species since March. By now the species numbers and the amount of individuals are just exploding after the early monsoon rains, and the diversity should increase for at least another month.

Mercury vapor light at Florida Canyon very early, later the density increased tremendously, but were to busy to take photos
At this time of the year, I try to go on bug safaris several times a week. That means coordinating participants arriving from different directions, driving to the canyons through washes and over protruding rocks, dragging around generators, batteries, mercury vapor lights, black lights, stands, sheets, cameras, and collection vials, hiding from thunderstorms and smugglers, chasing off bats and skunks, seeking out day-active species during three digit temps and raising humidity, staying out all night, coming home at dawn, identifying or posting the haul, counting chigger bites, accommodating collected ovipositing females and shipping the eggs to scientists across the continent,  ....who wants to actually organize a Moth Watching Week event?

But I'll be leading several public black lighting tours that are sponsored by Southwest Wings in Sierra Vista and by the Audubon Society of Tucson in August and September.

Pasimachus californicus prowling for bugs around the black light
During those events we will be looking for other insects and arachnids as well, but I know that even a big headed Pasimachus crawling onto the ground sheet has a hard time competing with the tumbling arrival of a big beautiful Polyphemus Silk Moth.

Carol swimming in moths
Last Thursday my friend Carol Tepper and I tried out my new MV light, taking advantage of the electricity outlets at the Santa Rita Experimental Ranch in Florida Canyon. Around the cabins and labs are rolling hills of mesquite grassland with ocotillos, yuccas, agaves, opuntias, and acacias, and  Mexican Blue Oaks, some sycamores and stands of hack-berries are lining the creek. Wild Cotton is now leafed out and as tall as I. Seep Willow emits its pungent swamp smell.
We left the black lights close to the creek and exercised our legs and lungs while carrying the MV stuff to the top of the hill, hoping that light would draw in an ocotillo specialist from the opposite slope (it didn't).

 Still, at both lights we were surrounded by insects, mostly moths, and they also covered the walls around several porch-lights that Mark, the station manager, kindly left on for us. I was noticed some distinct differences to my black light collection a week earlier at Madera Canyon (upper parking lot, juniper-oak habitat.

Chrysina beyeri, Jewel Chafers

Antheraea oculea
 Chrysina beyeri was the dominant beetle species at Madera Canyon, and of the great moths, the big polyphemus silkmoth Antheraea oculea was most impressive and numerous.

Hyalophora columbia gloveri
In Florida Canyon we didn't see any C. beyeri  and only one  cercopid Silkmoth moth, Hyalophora columbia gloveri. We waited in vain for its ocotillo-feeding relative, the dark Eupackardia calleta.

Eacles oslari, above and below

Instead, many specimens of Eacles oslari in a wide variety of color combinations came mostly to the MV light.

Caterpillar of Citheronia splendens on Wild Cotton
Last year we found this huge bizarre caterpillar on its host, a wild cotton plant in Florida Canyon. This year I finally got to see the big, plump adult moths Citheronia splendens sinaloensis.

While the big Silk Moths are most impressive, I also like the colorful Tiger Moths. I remember meeting a scientist in Portal who was collecting the pretty Bertholdia to study its ability 'to talk back to the bats'. This moth not only perceives the sonar of an approaching bat like many other insects who simply try to drop out of earshot, but it actually emits sounds of its own to throw off the bats echo beam.

Arachnis aulaea, Apocrisias thaumasta and Bertholdia trigona
Three Tiger Moths that were flying at Madera Canyon when I black lighted there a week ago..

Hypercompe suffusa and the delicate looking Halysidota davisii

Two representatives of the same subfamily at Florida Canyon. (When the taxonomy of this group of moths was revised lately, the Tigermoths became part of the family Erebidae).

Neoalbertia constans, Tetraclonia dyari (Madera) and Acoloithus novaricus (Florida)
Moths don't have to be huge or prettily patterned to be interesting. Here are some small Leaf Skeletonizers that are mainly day-fliers but also come to light traps. At Madera, there were two red Lycus (Net-Winged Beetle) mimics.  Fittingly, the beetles danced their mating flight around the oaks before sunset. At Florida only the little dark one on the right came to the light at night in numbers. This species is supposed to be mostly distributed in the eastern US.

Madera and Florida are geographically close to each other. They are two parallel canyons of the western Santa Rita Mountains, similar in orientation and both containing a stream that flowed only intermittently over the last drought years. Although oaks grow along most of both canyons, Madera is shadier and home mostly to Silverleaf Oaks while Florida is famous for its beautiful old Mexican Blue Oaks. The moth populations, though with many overlaps, also clearly express  the differences between the canyons. 

Wednesday, July 11, 2012

Net-winged Insects and the Strategies of their Predatory Offspring

There is great variety of species in the order Neuroptera, the net-winged insects, but they all have in common thin lacy wings, with forewings and hindwings of similar in size and shape, and biting chewing mouth-parts. Many species show some superficial similarity to Dragonflies, but they rest with their wings folded roof-like over their bodies. Their predacious larvae are terrestrial, except in Sisyridae. It's the larvae that show the most amazing strategies, from ambush in pits to chemical warfare. Neuroptera larvae pupate, often in a silky cocoon, and undergo a complete metamorphosis before hatching as winged adults.

Life cycle of a Common Antlion

Antlions are known to most people as the devious creatures that dig funnel-shaped pits in loose sand and not only sit in the bottom waiting for an unsuspecting ant that may fall in, but even throwing sand at their victims to make them loose their footing. I found them very difficult to photograph so I'm showing here an old illustration from Brehm's Thierleben (1895). The artist cheated: the larva on the left should be burried so only the pincer-shaped mandibles stick out of the sand. But I like the image because it shows the larva (left), the pupa (right) and the adult, winged antlion in the middle.
In North America only the antlions of the genus Myrmeleon dig those ant trapping pits. The larva in my picture was walking around openly catching insects under our porch light at night.

Vella fallax
An adult antlion Vella fallax was resting close by, but I'm not sure that this over 2 inch long adult was related to the larva.
Glenurus luniger
The diversity of antlion species in the desert around us is very high, they seem to be well adjusted to sandy soil and dry conditions (and lots of ants). But to see the pretty Glenurus luniger I have to take a trip to the mountains. This one is from Peppersauce Canyon in the Catalina Mountains.

Owlfly larvae
In Molino Basin, also part of the Catalinas, I found something that looked at first like a grass with dark seeds but turned out to be a group of first instar larvae of an owlfly. These young ones typically remain in a group with the original egg clutch for several days before dropping to the ground below and going their own predatory ways.

'trophic' eggs (left) and fertile eggs of Ululodes sp. photo by Hannah Nendick-Mason
 In the genus Ululodes the female provides her offspring with a series of club-shaped infertile eggs fastened below the regular eggs. These trophic eggs  (repagula) serve as the larvae's first meal and may prevent them from eating each other.

Also at Molino, this big owlfly was clinging to its perch so tightly that I could move it to find better light for my photos. Smaller species often appear at the black light, so they all seem to be night-active. Again, I do not know whether this is the same species as the clutch of larvae above.

Larvae of Brown and Green Lacewings
Meanwhile, at home, a strange shape is climbing a dried-up Brittle Bush. From above only a bunch of ant-body parts and exoskeletons is visible. The side view reveals legs and fangs that give away a Brown Lacewing larva. Probably very similar in built to the Green Lacewing Larvae that lived on the Brittle Bush flowers in spring, just smarter with its camouflage.

Green Lacewing eggs

Green Lacewing

 Adult Golden-eyed Green Lacewings are day-active and common year round. They feed on Aphids and other small insects. Their eggs sway on long stalks, protected from predators that come crawling along on the plant surface which may include their own older siblings.

Lomamyia sp., Berothidae (Beaded Lacewings)

Adult Beaded Lacewings are nocturnal and come to lights around our house in the desert bajada. They lay stalked eggs on wood surfaces near termite nests. The larvae move in with and prey on the termites. They discharge a gas containing an allomone  from their anus (Johnson and Hagen, 1981) to immobilize their prey.The gas is potent enough to paralyze several termite larvae and even adults at a time, but reportedly it has no effect on other non-termite 'house guests'.

Climaciella brunnea (Wasp Mantidfly)

When black-lighting for insects in the mountains, I often encounter several species of Mantid Flies.
They look and behave very much like small Praying Mantids. They use their raptorial arms to grab moths and other small insects that are also attracted by the light. In Arizona, the impressive Wasp Mantidfly lives in the canyons of the sky islands. While other morphs of that same species show brown and yellow banding of typical wasp mimicry, ours seems to mimic the coloration of Polistes comanche, the most common paper wasp of those habitats. Their larvae live as parasitoids in spider nests.