Photinus courtesy of Don Salvatore


Photinus ignitus interact with many species, whether it be by defending their lives from predators or trying to be the most attractive and fit male.  A Picture of a thrush courtesy of Sid Mosdellmost interesting interaction that Photinus ignitus fireflies have are with a variety of predators, including arthropods, birds, amphibians, reptiles, and fish.  Lacking size, strength, and speed (in comparison with predators), Photinus ignitus fireflies needed to balance out their weaknesses with a strength in order for survival.  Photinus ignitus gains protection over their main predators, thrushes and jumping spiders, by having steroidal pyrones known as lucibufagins (Lewis & Cratsley, 2008).  Lucibufagins are defensive steroids that make Photinus ignitus unpalatable (bad tasting) to predators (Eisner et. al, 1978).  Similar to other poisonous organisms, the predators that feed on Photinus ignitus learn to avoid them at each subsequent encounter. 

Photinus ignitus are considered lightning bugs because of their lanterns that luminesce at night.  In the Life History & Reproduction section of this website, you learn that fireflies, and more specifically Photinus ignitus, use theirGlowworm (another name for larvae) courtesy of Don Salvatore bioluminescence to locate and identify their mates during courtship.  This is not the only use for the variety of flashes and glows!  The larva use bioluminescence as a visual cue to predators to indicate that they are unpalatable and should be averted (Lewis & Cratsley, 2008).  As an adult firefly, the bioluminescence can be used in a different, interesting way.  Under certain circumstances of threat, such as being caught in a spider web, puddles, or tangles of grass, Photinus ignitus can emit a variety of flashes that are unlike those of courtship and mating (Lloyd, 2005).  These flashes most likely communicate a warning for other firefly’s to stay away. 

There are also many interactions within the species of Photinus ignitus.  One interaction in particular is that of an offering and accepting of nuptial gifts.  During the fascinating process of courtship and mating, Photinus ignitus males provide their female counterparts with nuptial gifts (Lloyd, 2005).  A nuptial gift is a food item or inedible token that could be used by a female for somatic maintenance and reproduction.  These nuptial gifts can include a variety of items such as spermatophores (a sperm-containing package), captured prey, or even an assortment of Picture of a nuptial gift, a spermatophore, courtesy of Tufts Universitymale body parts (Lewis & Cratsley, 2008).  The reasoning behind this contribution is for the female to use it as nutrients to provision her eggs (Cratsley, 2004).  Some species of fireflies, such as Photinus ignitus, do not feed as adults.  The male nuptial gifts provide the female with much-needed nutritional value to supplement her own maintenance in survival and reproduction.  Furthermore, the nuptial gifts will provide other benefits to the female, such as increasing lifetime fecundity, which is the potential reproductive capacity of the female firefly (Lewis & Cratsley, 2008).  Interestingly enough, studies have shown that for Photinus ignitus males, the ability to produce nuptial gifts, such as spermatophores, declines over each consecutive mating.  This has an impact over the lifespan of male Photinus ignitus fireflies because they will not be able to successfully mate as well towards the end of their limited lifespan (Cratsley & Lewis, 2005).

Bioluminescent fireflies (which includes Photinus ignitus) also interact with humans.  There are many applications of firefly chemistry, and here we will look at a few.  The light-producing chemicals taken from fireflies (luciferase) can be mass produced by injecting firefly genes in another organism, most likely bacteria, for increased production.  As mentioned in Fun Facts, luciferase is a chemical that can detect levels of ATP in cell, making it very useful in scientific research, food safety testing and forensic tests (Zielinski, 2013).  In terms of detecting ATP, NASA has even went as far as using firefly chemistry in search for life in space (Lloyd, 2005)!  The luciferase gene can also dramatically cut down the time it takes to diagnose a specific strain of tuberculosis.  Since tuberculosis has antibiotic medications that are strain-specific, time is essential in finding which strain is causing the dreaded disease, and this has shown to save many lives (Lloyd, 2005). 

Back to Home
Read about Fun Facts