Lifecycles

Insect Internal Anatomy

Dr. Natalie Hummel, LSU AgCenter Department of Entomology

E-mail: nhummel@agcenter.lsu.edu

9:45 to 10:15

Hemi-metabolousHemi = partial

-metabolous = changeIncomplete development

Larva looks similar to adult

Egg Nymph Adult

Chinch Bug

J. Saichuk

Rice Stink Bug

J. Saichuk

Aphids – a variation on this…

Amorochrous dubius

Holo-metabolousHolo = complete

-metabolous = changeComplete development

Larva looks different from adultRice Water Weevil

Egg Larva AdultPupa

J. Saichuk

Fall Armyworm

Rice Leafminer

J. Saichuk

J. Saichuk

Rice Levee Bill Bug

ColaspisColaspis

Rice water weevilRice Seed Midge

J. SaichukJ. Saichuk

J. Saichuk

SARMSkippersSkippers

J. Saichuk J. Saichuk

J. SaichukJ. Saichuk

R. Riggio

Feeding site

Head

R. Riggio

J. Saichuk

Puparia

J. Saichuk

A. Meszaros

J. Saichuk

Internal Anatomy

The Nervous System

Allows the insect to interact with the environment

Figure source Peng, UC Dacvis

The Brain

• Processes information

• Protocerebrum– Vision

• Deutocerebrum– Olfaction

• Tritocerebrum– Feeding

Figure source Chapman, 1998

How do Insects Sense the Environment?

Tarsal receptors are activated

Action potential

occurs

Message is sent to brain

Feeding commences

Figure source Peng, UC Dacvis

The Insect Circulatory System

• Circulates blood & hormones

• Hemolymph–Plasma ~ blood–Hemocytes ~ blood cells– Trehalose ~ blood sugar

• Pump (heart & dorsal aorta)• Diaphrams (Dorsal & Ventral )• Neurohormones control

Figure from Chapman, 1998

Figure from Chapman, 1998

Endocrine System - Hormones• Growth (molting)• Reproduction• Feeding• Mating

trw.umbc.edu/~vergil/Pix/insects.html trw.umbc.edu/~vergil/Pix/insects.html

Reproductive tract

http://images.google.com/imgres?imgurl=http://www.entomology.umn.edu/cues/4015/morpology/repro.jpg&imgrefurl=http://www.entomology.umn.edu/cues/4015/morpology/&usg=__JKdknStXraJP7-iF8w7zM5yjwS0=&h=375&w=594&sz=73&hl=en&start=6&sig2=RCZAkgjMqgh1q3MOzNewXA&um=1&itbs=1&tbnid=FFA3R1-4npnjNM:&tbnh=85&tbnw=135&prev=/images%3Fq%3Dinsect%2Breproductive%2Btract%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26sa%3DG%26rls%3Dorg.mozilla:en-US:official%26tbs%3Disch:1&ei=t6aGS9KhAaWKNbmozfAL

Digestive tract

http://www.earthlife.net/insects/images/anatomy/guts.gif

The Big Picture – Endocrine system

Figure source Peng, UC Dacvis

The Insect Tracheal System• Oxygen & waste products to & from each cell

• Tracheal system– Spiracles– Trachea– Taenidia– Tracheoles– Tracheolar cells

Figure Snodgrass, 1935

Figure Snodgrass, 1935

http://www.nature.com/nrg/journal/v1/n3/images/nrg1200-218a-f4.jpg

References

• Chapman, R.F. 1998. The Insects: Structure and Function. Cambridge University Press. NY, NY USA.

• Snodgrass, 1935. Principles of Insect Morphology

• Online resources, as cited in slides.• Peng, C.Y.S. Insect Physiology Lab Manual.