An online resource based on the award-winning nature guide

Insects

Monarch Butterfly

This 15-minute-old monarch butterfly that emerged yesterday will live for 2 to 5 weeks, long enough to mate and produce the next generation of monarchs.  The generation of monarchs that emerges a month or more from now will live six to nine months, and not mate until next March or so – after flying  to one of about a dozen locations in the Transvolcanic Mountains of central Mexico (a flight of up to 3,000 miles) and spending  the winter.  Late summer-emerging monarchs live longer than monarchs that emerge earlier in the summer because they do not immediately expend energy on breeding and the cool winter temperature in Mexico slows their metabolism, allowing them a longer life.

 


Cecropia Moth Caterpillar

The larval stage of the Cecropia Moth ( Hyalophora cecropia), a giant silk moth, is a sight to behold.  The yellow, blue and red knobs that adorn its 4″ pale green body are striking.  Look for this caterpillar on apple, ash, box elder, cherry, lilac , birch, maple and poplar trees, whose leaves it consumes with relish.  The larva spins a brown, spindle-shaped, 3” cocoon in the fall, and overwinters as a pupa inside it.  In the spring, the adult Cecropia Moth , North America’s largest native moth, emerges.  Brown, with a 4” to 5” wingspread, it has no mouthparts, and lives only about a week to ten days, during which time the males mate numerous times, and the females lay eggs. Unfortunately, this species of moth seems to be declining in number, in part because it suffers from parasitism by a fly that was introduced to control the Gypsy Moth.

 


Dragonflies and Temperature Control

Often on hot, sunny days you will see dragonflies perched facing away from the sun, with their abdomens raised high in the air above them.  This position actually has a name – the obelisk posture – and some dragonflies and damselflies assume this position to prevent overheating.  They raise their abdomen  until its tip points at the sun, minimizing the surface area exposed to it.  The name given this posture comes from the fact that when the sun is directly overhead, the vertical alignment of the insect’s body suggests an obelisk. The meadowhawk dragonfly in the photograph  assumed  the obelisk posture several seconds after the sun came out from behind  the clouds.  As soon as the sun was obscured by clouds again, the dragonfly would lower its abdomen to a horizontal position. It continued doing this for a considerable amount of time.  Sometimes abdomens are raised for reasons other than temperature control, including threat displays during conflicts.


Leafhoppers

Leafhoppers belong to the family Cicadellidae — one of the largest families of plant-feeding insects.  There are more leafhopper species worldwide than all species of birds, mammals, reptiles, and amphibians combined.  Certain species, including the pictured red-banded leafhopper,Graphocephala coccinea, drink the watery sap from the plant’s xylem tissue, and secrete honeydew, a sugar-rich solution which ants love.  The ants protect the leafhoppers against predators in return for this sweet treat (an arrangement they also have with aphids).


Dragonflies Mating

7-19-11  Mating Dragonflies

Dragonflies (and damselflies) form what is called a “mating wheel” when they mate.  The male (top) grasps the female at the back of her head with the appendages at the tip of his abdomen. The female then curls her abdomen forward so that its tip reaches his sex organs and receives his sperm.  After mating, the male may continue to grasp the female and accompany her while she lays her eggs, to prevent another male from removing his sperm from the female and then mating with her.

 


Robber Flies

Robber flies often perch on the leaves or stems of low plants waiting until suitable prey flies by, and then attack it in the air.  They have long, strong, spiny legs for grabbing prey, and piercing-sucking mouthparts for consuming it.  Robber flies prey on a variety of insects, including bees, beetles, bugs, dragonflies, grasshoppers, flies, leafhoppers and wasps. Once they capture an insect, they pierce it with their short, strong proboscis, or mouthpart, and inject  their saliva into it.  The saliva of robber flies contains enzymes that paralyze the insect and digest its insides, which the robber fly then drinks. The pictured robber fly is feasting on the innards of a stink bug it just captured.