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FIGURE 1. Fireflies and Lightning Bugs are one and the same, but it seems they’re referred to more as Lightning Bugs to us Southerners. Shown above is top (dorsal) view of Photinus sp.
 

   
 

 

FIGURE 2. Shown above is side (lateral) view of Photinus sp.

   
 

 

FIGURE 3. Few other insects can be confused with Lightning Bugs because other insects do not possess such light-producing structures on their abdomens.

   
 

 

FIGURE 4. Larvae of most species of Lightning Bugs are specialized predators and feed on other insect larvae, snails and slugs. (Photo by Gerald J. Lenhard, www.forestryimages.org)

   

Quick Facts

Common Name:

Lightning bug

Other Common Name(s):

Firefly & lightning beetle

Genus / Species:

Photinus sp. (in Texas) 

Type of Beneficial:

Insect predator

Type of Metamorphosis:

Immature stages appear different from the adult stage (i.e., complete metamorphosis)

Beneficial Stage(s):

Immature stages are predators. Adults of some species are also predatory

Prey:

Larvae of most species are specialized predators and feed on other insect larvae, snails and slugs. (They are also reported to feed on earthworms.) Adults of some species are also predatory. Adults of some species apparently do not feed.

Occurrence:

Due to urban sprawl over the last few decades, large swarms of lightning bugs are a less frequent occurrence across the Galveston-Houston region; however, small swarms still occur, primarily away from city lights and in more open areas of vegetation.

Mounted Specimen?

Not yet!

 

Do you remember how much fun collecting Fireflies was in the summertime when you were a kid? There was always something magical about the way they lit up.

I would collect them in a peanut butter jar with a lid of punched out holes for air, trying to catch as many as I could for a more spectacular light show. After a few hours of gazing through the lit jar, I would set them free. I remember always dreaming of living in a land of fairies and Fireflies, where there would always be flowers and twinkling lights!

Recently I saw a bug collecting kit at a thrift store, one of my favorite hangouts in search of small inexpensive treasures and a wonderful place to daydream—and it all came back to me. I thought everyone might enjoy a trip down memory lane and perhaps learn a little about Fireflies—and guess what? They’re not flies at all—they’re beetles!

Description

Fireflies and Lightning Bugs are one and the same, but it seems they’re referred to more as Lightning Bugs to us Southerners. Moreover, entomologists advocate that a more accurate common name for these insects would be "lightning beetles" because they are neither flies (which belong to Order Diptera) nor true bugs (Order Hemiptera). Lightning Bugs are classed in Order Coleoptera: Family Lampyridae. Commonly seen Lightning Bugs in Texas include Photinus sp. and Photuris pennsylvanicus (the woods firefly).

Few other insects can be confused with Lightning Bugs because no other insect possess the light-producing structures on their abdomens, although some click beetles (Order Coleoptera: Family Elateridae) also have light-producing structures on their bodies.

Lightning Bugs are winged beetles. Adults are 7/16 to 9/16 inch long, elongate and very soft-bodied, with the pronotum extending forward over the head, resulting in the head being largely or entirely concealed when viewed from above. The pronotum is reddish-yellow with a black spot in the center. Brownish-black wing covers have a light yellowish area entirely around them except in front.

The luminous lower end of a male Firefly's abdomen is yellowish-green, whereas the female has a smaller splotch. It is these "taillight" segments where living light is produced. Eggs secreted in the earth may show a touch of luminescence.

Reproduction

Larval stages of Lightning Bugs have three pairs of legs and are turtle-like creatures with tiny spots on their underside, softly glowing like view holes in the furnace door. Wingless females and luminescent larvae are often called "glowworms."

There are over 136 species of Lightning Bugs, each with a distinctive rate of flashes per second. The flashes are produced by a chemical called luciferase, which they use to attract the opposite sex. The summer evening light shows that you see are performed by male Lightning Bugs.

Male Lightning Bugs flash patterns of light to females. The females signal in response from perches in or near the ground. When the male sees the female's flash he continues to signal and moves closer. Eventually, through a series of flashes, they find each other and mate. Each species of Firefly sends different mating signals.

The favorite “hangouts” of Lightning Bugs are east of the Rocky Mountains and away from city lights. A few days after mating, which occurs in the spring, a female lays her fertilized eggs on or just below the surface of the ground. The eggs hatch 3-4 weeks later and the larva feed until the end of the summer. Lightning Bugs overwinter as larvae buried in the soil and emerge in the spring to feed.

Beneficial Role

Whether you know them as Lightning Bugs or Fireflies, these are beneficial insects. They don't bite, they have no pincers, they don't attack, they don't carry disease, they are not poisonous, they don't even fly very fast. The larvae of most species are specialized predators and feed on other insect larvae, snails and slugs. (They are also reported to feed on earthworms.) Adults of some species are also predatory. Adults of some species are reported as not feeding.

These wonderful beetles are also helping humans. The Lightning Bug contains luciferin and luciferase, two rare chemicals used in research on cancer, multiple sclerosis, cystic fibrosis and heart disease.

Beneficials in the Garden & Landscape is an Earth-KindTM program coordinated through Extension Horticulture at Texas A&M University. Earth-Kind uses research-proven techniques to provide maximum gardening and landscape enjoyment while preserving and protecting our environment.

 

This web site is maintained by Master Gardener Laura Bellmore, under the direction of William M. Johnson, Ph.D., County Extension Agent-Horticulture & Master Gardener Program Coordinator.

All digital photographs are the property of  the Galveston County Master Gardener Association, Inc. (GCMGA) © 2002-2006 GCMGA - All Rights Reserved.