Moths (Lepidoptera)

Life Stages

     Moths have similar metamorphic life cycles as butterflies. They transition through 4 separate stages, from egg to moth. Moths generally lay up to 20,000 microscopic eggs under host plant leaves. These plants are called hosts because once the moth eggs hatch into caterpillars, the caterpillars will feed on the leaves until they are big enough to pupate. Caterpillars will hatch generally in 1-2 weeks. The caterpillar will then take 2-4 weeks to grow, continuously shedding its skin as it grows. Each shed is called an instar, and caterpillars will typically go through 5-10 instars in their caterpillar stage of life. Along with growing in size, during each instar caterpillars typically will also change color, and some may loose appendages. The caterpillar will then pupate for 2 weeks to many months. Caterpillars pupate in a variety of different ways. Among the most common ways are spinning a silk cocoon around themselves, or gathering up leaves to make a cocoon with leaves and their silk. Once the pupae hatches into a moth, the moth will spend a small amount of time strengthening their wings. The moth will hang off a plant and pump its wings in preparation for flight. Once a moth is born, it will typically live for 2 weeks to 2 months before it dies and completes its life cycle.

   Reproduction 

Clearwing moths Synanthedon bibionipennis 

Mating in Douglas County, Oregon. 

Male on left, female on right. 

http://bugguide.net/node/view/351373/bgpage

 

     Moths begin their search for a mate immediately upon leaving their cacoons. Mating begins when the female moth releasing sex pheromones telling the males she is ready. The release of sex pheromones happens before sunrise which is the typical time for moths to mate. The male moth will find a female by
sense of smell, and the female and male will then attach themselves at the abdomen. The male then passes a sac known as a spermatophore to the female which she will store in her abdomen's reproductive center. The female then incubates the eggs for a period of time and then deposit an egg stick ranging in number of eggs onto a host plant. The eggs will then go through metamorphosis until they become adult moths themselves. Moths typically mate 3 to 4 times in their lifetime. An adult moth will live for 9 to 11 days. 

       

    

   

Anatomy

     The moth is an arthropod, meaning it has a segmented body and legs. One defining characteristic of moths and butterflies is their proboscis, a long straw-like structure that it uncurls to feed. Moths use their antennae to smell, and fore legs to taste. They have three pairs of legs, 6 legs in total. The thorax contains wing and leg muscles as well as the tympana or "ears". Moths can use their tympana to detect vibrations, which they use for avoiding predators. The abdomen of a moth contains vital organs for reproduction, breathing and digestion. 

     The anatomy of a moth is different from a butterflies in a few distrinctive ways. Moths have a frenulum, which is a wing-coupling device that butterflies do not have Frenulums join the forewing to the hind wing, so that the wings can work in unison. Moths also tend to hold their wings closer to their bodies. The other key difference is that a moth pupa can make silk while a butterfly pupa cannot.

Pollination 

      Moths are night pollinators and generally pollinate white flowers because they are easy for the moths to see at night. Bats are also night pollinators, however it is easy to distinguish between the two because moth pollinated plants tend to smell sweeter. Producing a fragrance is very costly for a plant. However since the plant relies on its scent to attracts their pollinator, most night pollinated plants produce a stronger fragrence at night when they are more likely to get pollinated. Moth pollinated plants typically have long spurs, or tube like structures that contain nectar within their flower. Moths use their proboscis, a long tongue/straw like structure they uncurl and insert into the flowers spur to suck up nectar.

     Moths have a mutualistic relationship with the plants they pollinate. Orchids are commonly pollinated by moths, trading pollination for food. All moth pollinated orchids are perfect, meaning their flowers are made up of both make and female components. Orchids are also the only flower with a pollinia, a pollen package attached to a viscus disk that is located near the top of the flower. The moth inserts its proboscis into the orchids spur to get nectar, and on the way out the orchids pollinia will break off and attach itself to the moths proboscis with its sticky viscus disk.The moth will then go into a second flower to get nectar, unaware that it is pollinating the flower at the same time. The moth will drag the pollinia across the stigma, the sticky male part of the flower, and the pollinia will get attached to the stigma on the proboscis's way to get nectar. The moth thus completes the pollination of the orchid, grabing another pollinia to deliver at the same time it pollinated the first flower. Each orchid only has one pollinia, so it is extremely important for it to attract the right pollinator and provide a reward to insure pollination. Some moths have co-evolved with the flowers that they pollinate like this hawkmoth on the left. Co-evolution means that the moth evolved with the flower evolving a proboscis that fit inside the flower.

 

five-spotted hawkmoth (Manduca quinquemaculata)

pollinating using its proboscis

Resources:
http://home.cogeco.ca/~lunker/stagesmoth.htm
http://www.animalcorner.co.uk/insects/moths/mothlifeanatomy.html
Doug, UW Greenhouse
http://jeb.biologists.org/content/210/15/2637.full
http://www.loc.gov/rr/scitech/mysteries/butterflymoth.html