Saturday, March 28, 2009

Sphingidae

I caught this sphinx moth, also known as a hummingbird moth, outside one of the places I work. They are extremely common and can be seen from morning to night, hovering and drinking nectar from flowers with a long proboscis. They truly resemble hummingbirds in size and style of feeding, with rapidly beating wings. I have included a picture of the specimen while pinned, in addition to the crane fly from the other day.




Lepidoptera; Bombycoidea; Sphingidae; Macroglossinae; Macroglossini; Hyles lineata
Common Name: White-Lined Sphinx Moth

Sphinx moths usually have rather large bodies, narrow wings, and in the case of the above species, extremely long proboscises. The larvae are usually green hornworms, which are major agricultural pests. One species' larvae is a common agricultural pest, the tomato hornworm. Others feed on tobacco and other plants. However, the larvae are also often attacked by parasites like braconid wasps.


Thursday, March 26, 2009

Tipulidae

This specimen is a member of the family Tipulidae, and has become very abundant this time of year in San Diego. They are often mistaken as "giant mosquitoes" or are labeled "mosquito eaters". There are over a thousand species from this family in North America.



Diptera; Tipulomorpha; Tipulidae
Common Name: Crane Fly

It is difficult to narrow down the genus without a key specific for Tipulidae. This family contains flies with long thin abdomens, long narrow wings, and extremely long legs. They are often found dancing around artificial lights or across grassy fields. The females have pointed abdomens, while the males have rounded abdomens. Crane fly larvae bear the common name "leatherjackets" and consume roots and plant material, while the adults may consume nectar. They have a very ephemeral adult phase - the main objective is to mate. They do not bite or sting, and are easily captured.

Tenebrionidae

I already posted a specimen from Tenebrionidae, however this is a very common species of Tenebrionidae, and I felt compelled to share. Unlike the other specimen I posted, this species has no hair-like extensions on the elytra (top abdominal shell). Most of the members of Tenebrionidae are absent of hair (setae). Members of Tenebrionidae are also known as Darkling Beetles, and their pupa are various meal worms.





Coleoptera; Polyphaga; Tenebrionoidea; Tenebrionidae; Opatrinae; Eleodes dentipes
Common Name: Darkling Beetle, "Stink Bug" (misnomer)

These insects are commonly mistaken as "Stink Bugs" when they are neither bugs (order Hemiptera, compared to order Coleoptera), nor is that their official common name. An example of a stink bug can be seen here. True stink bugs come in colors ranging from green, to brown, to black and red. The insect pictured above is most likely associated with stink bugs because if disturbed it raises its pointed abdomen into the air as if to spray a chemical, and when crushed they smell very unpleasant. I am not positive on my identification of the species, but the genus is definitely Eleodes. They can be differentiated from Carabidae, another common family of ground beetles, by having a body raised off the ground and small jaws.

Tuesday, March 24, 2009

Coenagrionidae

By sheer coincidence, the latest insect I have captured is also a member of Odonata, but a different family. I already have three representatives of Coenagrionidae in my collection, so I only took live photos of this one then let her fly away. Coenagrionidae are damselflies, which go by the common family name of "Pond Damsels" or "Narrow Winged Damselflies." This is a very large family, and they range in length from 20mm to 50mm. They mostly occur along streams and still bodies of water. They hold their wings together over the body when at rest, unlike dragonflies which hold their wings flat, perpendicular to their body orientation. Coloration can vary, including blue, purple, red, orange, yellow, black and green, in different combinations.







Odonata; Zygoptera; Coenagrionidae; Ischnura denticollis
Common Name: Black-fronted Forktail

Black-fronted forktails are very common in Southern California. The one pictured above is a female, and thorax is gray with purple eyes, and a single blue band at the tip of the abdomen. Males have a blue thorax and eyes. This specimen was caught in downtown San Diego.

Odonata - Anatomical Discussion

Per request, I have taken some detailed photos of two of my dragonfly specimens, both members of the family Libellulidae. The name of the order is actually based on their strong, chewing, toothed mandibles - "odonto" is Greek for "teeth". The diagrams are taken from Borror and Delong's Introduction to the Study of Insects, 7th Edition.







The relevant abbreviations from above - 1st diagram: lg, ligula or median lobe; mn, mentum; p, palp or lateral lobe; plg, palpiger or squama; 2nd diagram: fr, frons; pclp, postclypeus; aclp, anteclypeus; lbr, labrum; md, mandible; mx, maxilla; lbm, labium; e, compound eye;

I should add that the characteristic which distinguishes Odonata from other insect orders is the location of the copulatory organs, which are located on the anteior end of the abdomen on males, on the underside between the second and third segments. Due to the location, when dragonflies mate their bodies form a circle, known as the "wheel position".

Sunday, March 22, 2009

Libellulidae

This specimen was caught on a wall on campus at UCSD. It is a member of the family Libellulidae, and I searched for the genus-species, but it is such a large family that it would be difficult to identify without a key. The family Libellulidae is one of the largest dragonfly families, and is mostly found in the New World. The wingspan is approximately four inches, body length 2.5-3 inches.




Odonata; Anisoptera; Libellulidae;

The life cycle of dragonflies begins in ponds, where nymphs spend up to four years developing to the point where they are ready to metamorphose. They are significant pond predators, growing large enough to eat small fish. When they metamorphose, they emerge with wings and feed and search for mates. They are formidable aerial predators as well, with extremely good vision and speedy flight. Be careful when handling, as they may bite.

Thursday, March 19, 2009

Scarabaeidae (Part 2)

As promised, here is the other representative of the scarab family that I have collected - two specimens, one wings spread, the other wings closed. They were both found around twilight, are not known to bite, and are approximately 1cm to 1.5cm long, and 7 mm wide.







Coleoptera; Polyphaga; Scarabaeoidea; Scarabaeidae; Dynastinae; Cyclocephalini; Cyclocephala lurida
Common Name: Southern Masked Chafer

Masked Chafers are beetles native to North America, and an agricultural pest across the country, though is most common in the southern states. They tend to be a dull yellow-orange color, with a dark head. Their distinguishing characteristics as a genus include a rounded clypeus (frontal mouth plate) and a relatively large fifth foot segment, or tarsomere. The species attack the roots of plants, particularly turfgrasses. The larvae are large white grubs, about 8 mm long, and gradually darken to a reddish color before they pupate into adult beetles.

Saturday, March 14, 2009

Scarabaeidae

Since finals are right around the corner (next week) I have been rather busy and unable to go collect insects. Also, the weather has been pretty cold, so not much insect activity has been going on - even my captive caterpillars are less active and show less appetite. All the same, I feel it necessary to update periodically. One of my favorite insects is the green fruit beetle, a large common scarab beetle in San Diego county.




Coleoptera; Polyphaga; Scarabaeoidea; Scarabaeidae; Cetoniidae; Gymnetini; Cotinis mutabilis
Common Name: Green Fruit Beetle; Fig Beetle;

People call them "fig beetles" as well, since they are found eating figs and there are a lot of fig trees down here. There is a particularly huge one down at Balboa park and if you go there during the summer, you will inevitably see a few crushed green scarab beetles or they'll be flying awkwardly around the trees. They do not bite but their legs have very sharp claws. This specimen is a bit larger than average, about 1 and 1/4 inches long, 3/4 inches wide, and 1/2 inch high. Their larvae are about 1 inch long, white, and wrinkly in appearance. I was considering including a second scarabaeoid beetle in this entry, but it will have to wait - too tired to look up the likely species. Hopefully I will go collecting next week! I may also have a special feature on Grunions, as the Grunion runs are upon us here in San Diego!

Sunday, March 1, 2009

Dipteran and Chilopoda (Centipede)

I went on an excursion today to try to find new insects. The usual trail was open again, so we went and I collected insects and more caterpillar feed. I decided to get some leafy ground weeds since grass is hardly nutritious and these caterpillars seem to crave variety in their diet. Most of the wild ones were smaller than my six, so I must be doing something right.

As for the non-insect specimen collected today, here are lovely pictures:





Arthropoda; Chilopoda; Scolopendromorpha; Scolopendridae; Scolopendra polymorpha
Common Name: Common Desert Centipede

This species comes in a variety of colors, hence the species name polymorpha. Its color range includes orange, yellow, blue, red, and various light-dark combinations. They tend to take cover under rocks and consume small insects, particularly crickets. It can reach a length of up to 5 inches and is common in the southwest United States.

By the by, I am going to need a new camera, specifically for macro photographs. I love the macro on my current camera, but for creatures smaller than 10 mm it just does not do them justice.