Reproductive Anatomy of Insects Study Notes PDF

Created by Turbolearn AI Reproductive Anatomy of Insects Male Reproductive System The male reproductive system consists of: Testes: produce sperm Vas deferens: store sperm Ejaculatory duct: transport sperm out of the body Aedeagus (also known as penis): the external genital or...

Created by Turbolearn AI Reproductive Anatomy of Insects Male Reproductive System The male reproductive system consists of: Testes: produce sperm Vas deferens: store sperm Ejaculatory duct: transport sperm out of the body Aedeagus (also known as penis): the external genital organ used for mating "The aedeagus is a complex structure that varies greatly in shape and size among different insect species. It is used for transferring sperm to the female during mating." Female Reproductive System The female reproductive system consists of: Ovaries: produce eggs Oviduct: transport eggs out of the body Spermatheca: a sperm receptacle and storage organ that allows females to control fertilization Ovipositor: the external genital organ used for laying eggs "The spermatheca is a unique feature of female insects that allows them to store sperm from multiple males and control fertilization. This is an example of cryptic female choice, where females can choose which sperm to use for fertilization." Mating and Courtship Behaviors Insects use various strategies to find mates, including: Page 1  Created by Turbolearn AI Swarming: large groups of insects gather in a specific location to increase the chances of finding a mate Pheromones: chemical signals released by females to attract males Hilltopping: males gather at the top of a hill or mountain to establish territories and attract females Song: some insects use sound to attract mates Vibrational cues: some insects use vibrations to communicate with potential mates Light signals: some insects use light to attract mates Examples of Mating and Courtship Behaviors Insect Mating Behavior Butterflies Hilltopping, pheromones Moths Pheromones, light signals Fireflies Light signals Orthopterans Song, vibrational cues Impressing a Mate Once a mate is found, insects use various courtship rituals to impress each other, including: Dancing: complex movements used to attract a mate Fighting: males engage in combat to establish dominance and attract a mate Gift-giving: some insects offer food or other gifts to potential mates These courtship rituals serve to increase the chances of successful mating and ensure the survival of the species.## Nuptial Gifts Nuptial gifts are presents given by males to females during courtship to increase their chances of mating. These gifts can be food items, such as dead prey, or even nutrients like sodium. Types of Nuptial Gifts Page 2  Created by Turbolearn AI Spermatophore: a package of sperm and nutrients given by males to females during mating. Food items: dead prey items, such as moths, given by males to females to provide them with nutrients. Examples of Nuptial Gifts Type of Species Nuptial Description Gift The male scorpionfly gives a dead moth to the female as Scorpionfly Dead moth a nuptial gift. Male tiger swallowtails collect sodium from puddles and Tiger Sodium transfer it to their spermatophore, which is then given to swallowtail the female during mating. Sexual Dimorphism Sexual dimorphism is the difference in form or structure between males and females of the same species. Examples of Sexual Dimorphism Species Description Peach tree The male has a wasp-like appearance, while the female has an borer orange and black coloration. Tiger The male and female have different color patterns on their wings. swallowtail Pinning and Insect Collections Pinning is the process of attaching an insect to a pin for preservation and display. How to Pin Insects Page 3  Created by Turbolearn AI Pin placement: The pin should be placed through the thorax of moths, the top right abdominal segment of beetles, and the metathorax of flies. Pin angle: The pin should be perpendicular to the insect, at a 90-degree angle. Examples of Good and Bad Pinning Pinning Description Method The pin is placed through the thorax and is perpendicular to the Correct pinning insect. Incorrect The pin is placed too low, too high, or at an angle. pinning Keys to Identification A key is a tool used to identify the order, family, genus, and species of an insect. Types of Keys Pictorial key: a key that uses images to guide the user through the identification process. Dichotomous key: a key that presents two choices at each step, leading the user to the correct identification. Example of a Pictorial Key "Wing or no wings?" If the insect has wings, go to page 18. If the insect does not have wings, go to page 27. Example of a Dichotomous Key "Is the insect a beetle?" Page 4  Created by Turbolearn AI If yes, go to the key to the families of beetles. If no, go to the key to the orders of insects.## Identifying Insects using Keys What is a Key? A key is a tool used to identify insects by examining their characteristics and traits. It is a series of couplets, each describing a specific characteristic, that lead to the identification of the insect. How to Use a Key To use a key, start with the first couplet and determine which characteristic is present in the insect. Then, follow the instructions to the next couplet, and continue until you reach the identification of the insect. Example of a Key Next Couplets Characteristics Step 1 Lateral margins of primordum granular with numerous setae 2 Lateral margin of crinonum not granular and with a single row 49 of cetae 2 Number of antenna segments is 9 3 Number of antenna segments is 8 48 3 Number of lamellae in antennae is 3 4 Number of lamellae in antennae is 4 29 Number of lamellae in antennae is 5 36 Published Keys Published keys are developed by experts in the field and are used to identify specific groups of insects. They are often more detailed and complex than simple keys. Page 5  Created by Turbolearn AI Example of a Published Key Key to the Primary and Secondary Parasitoids, known from Lyme coatings in North America Couplet 1: Hind wing modified with a haltere. Figure 1: Arrow pointing to the haltere. Is it a fly or a wasp? Couplet 2: Ocular setae. Figure 8: Arrow pointing to the ocular setae. Is the ocular setae present or absent? Characteristics Used in Keys Haltere: A small, usually knob-like structure at the base of the hind wing in flies. Ocular setae: Sensory hairs on the head of an insect, near the eyes. Lamellae: Thin, plate-like structures in the antennae of some insects. Pleuron: A part of the thorax in insects, often with a groove or other characteristic features. Tips for Using Keys Start with the first couplet and follow the instructions carefully. Use a hand lens or microscope to examine the characteristics of the insect. Be patient and take your time, as using a key can be a slow and detailed process. Practice using keys to become more familiar with the characteristics of different insects. Page 6