Nuptial Gifts

Question 1

What are nuptial gifts?

Answer 1

Common in human courtship

Natural gifts seem to come and less interesting ornamentation or weaponry

However, it played an important role in the mating system

Question 2

What non-gametic materials are typically transferred from males to females during courtship?

Answer 2

Lipids carbohydrates, proteins, peptides, amino acids, uric acid, minerals, water, antipredator defence compounds and a chemical that induce a physiological response

Question 3

Sperm competition

Answer 3

Thought to be the primary reason while males of a natural gifts to females and allow females to cannibalism

Question 4

Nuptial gifts as mating effort

Answer 4

The males paternity and the number of sperm he transfers often correlates with the size of the gift

Question 5

Forms of animal nuptial gifts

Answer 5

Food offerings, various male body parts (all the whole male), hemolymph, salivary gland secretions, seminal fluid, spermatophores and ’love darts’

Question 6

Net fitness benefit on males

Answer 6

The collection and manufacture of nuptial gifts is costly for males

The gift given males must able to sire a more offspring than other males in the same population

Question 7

Seven episodes of selection for male gifts.

Answer 7

1. Mate attraction
2. Copulation
3. Insemination
4. Sperm transferred
5. Sperm storage
6. Paternity share
7. Female fecundity
8. Egg and offspring survival

Question 8

Exogenous oral gifts

Answer 8

This consists of food items that males capture all collected, so generally contain nutritive material- these gifts are protected to deliver net fitness to benefit the females

Question 9

Three ways these gifts are generally predicted to increase male fitness

Answer 9

1. They can be assessed visually prior to meeting, exogenous oral gifts should affect a mates ability to attract females
2. Females remain stationary while feeding, food gives make it easier for males to initiate population
3. Females feed on these gifts while copulating, these gifts are expected to increase both copulation duration and quality of sperm transferred

Question 10

Endogenous oral gifts

Answer 10

These are secretions made by the males salivary, reproductive and other glands, as well as other parts of the male body

Question 11

How do these gifts help males increase fitness?

Answer 11

They can be inspected by the females, they could resemble exogenous gifts

Males may be selected to incorporate phagostimulants the increase the gifts gustatory appeal and also to alter gift composition to slow female consumption rates

Question 12

Cricket example

Answer 12

In some ground crickets, females imbibe hemolymph from a specialised spur located on the mates hindlegs

Question 13

Cockroaches example

Answer 13

In cockroaches, males augment their spermatophores to be important nitrogen source for females and their eggs

Question 14

Mantids and orb-weaving spiders example

Answer 14

These engage in sexual cannibalism were females kill and consume males either before or after insemination

Question 15

Endogenous genital gifts

Answer 15

These are materials that are produced by the secretory tissue in the male reproductive tract, transferred in seminal fluid, or spermatophores and absorbed through the female genital tract

Like orally-ingested glandular gifts, these products of male reproductive glands can also supply nutrients that absenct or limited within females diets

Question 16

Endogenous genital gifts and defensive compounds

Answer 16

These can contain defensive compounds that protects the female or her eggs against predators or microbial attack

Question 17

Endogenous genital gifts and female fitness

Answer 17

These may reduce female fitness

In some species, male gifts contain anti-aphrodisiacs into reduce a females likelihood of remating

Selection on males to reduce sperm competition risk favour inclusion of such substances, butanti-aphrodisiacs can lower female net fitness it they overly depress remating rates

Question 18

What are endogenous transdermal gifts?

Answer 18

Male seminal and glandular products that are transferred and absorbed outside the females digestive or reproductive systems

This happens during extragenital insemination in bedbugs

Selection on transdermal gifts may favour the inclusion of compounds that benefit males but may be detrimental to female fitness

Question 19

What is a love dart?

Answer 19

A sharp, calcareous or chitinous dart that some hermaphroditic land snails and slugs create

The love dart is not a penial stylet- the exchange of sperm between the snails is a completely separate part of the mating progression

The dart can strongly favour the reproductive outcome for the snail that is able to lodge a dart in its partners - the mucus on the dart introduces a hormone-like substance that allowsfar more of its sperm to survive

Question 20

Gift giving- heteropteran Zeus bugs

Answer 20

Males feed upon glandular secretions provided by the female

A male Zeus bug clings to the back of a female. The nuptial gift to him is a place to stay while they mate, complete with snacks

Question 21

Evolution of worthless gifts

Answer 21

The evolution of worthless gift-giving is potentially favoured when the male may reduce the cost of gift production by eating the prey before offering it to females or by offering inedible items

Males seem to hold the upper hand in this co-evolutionary cycle, unless females counteract the deception via some postcopulatory process