Nuptial Gift: Materials beyond the obligatory gametes that are transferred from one sex to another during courtship or mating (Lewis and South 2012).
In nature, the race to reproduce is incredibly competitive. Success means an organism passes on its genes; failure means that the organism’s specific genes are lost to the gene pool. One way in which an organism can increase its chance of reproduction is the presentation of a nuptial gift.Lewis and South (2012) define a nuptial gift as “...materials beyond the obligatory gametes that are transferred from one sex to another during courtship or mating.” Note that this definition does not specify the sex of the giver or the receiver. Whereas male to female gifts are the most common variety of nuptial gift, some species show evidence of female to male gifts (Arnqvist et al. 2003). Male Zeus bugs (Phoreticovelia disparata) feed on female glandular secretions while mating. There is also precedence for nuptial gifts in hermaphroditic species (Koene et al. 2005). Earthworms (Lumbricus terrestris) inject their copulatory partners with a substance that increases sperm uptake.
Diversity of Nuptial Gifts
Nuptial gifts are diverse; they can take the form of lipids, proteins, carbohydrates, peptides, uric acids, amino acids, water, pheromones, minerals, and anti-predator compounds, just to name few. Because of this diversity, it is helpful to categorize nuptial gifts in several ways. Gifts can be either endogenous or exogenous in nature (Lewis and South 2012). Endogenous gifts are gifts produced by the giver’s body. Exogenous gifts are food items procured by the giver from the environment. Similarly, nuptial gifts can be oral, genital, or transdermal in nature. Oral gifts are consumed through the receiver’s mouth (Gwyne 2008). Oral gifts assist the giver in mating by occupying the receiver and prolonging copulation (Lewis and South 2012). Genital gifts are consumed through the receiver’s genitals. Transdermal gifts are gifts that are consumed neither orally nor genitally, but injected through the receiver’s skin.
Common Types of Nuptial Gift
Exogenous Oral Gifts: An exogenous oral gift is a gift that is received orally but is not created by the giver. An example of an exogenous oral gift would be food items, such as is displayed in nuptial feeding (Lewis and South 2012). In many species of bird, males provide females with food during courtship or incubation (Silver et al. 1985).
Endogenous Oral Gifts: An endogenous oral gift is a gift that is received orally and generated by the giver’s body. Female sagebrush crickets (Cyphoderris strepitans) feed on wings of males during copulation (Eggert and Sakaluk 1994). Chewing on the male’s wings occupies the female cricket and prolongs copulation.
Endogenous Genital Gifts: An endogenous genital gift is a gift created by the giver and given to the receiver through its reproductive tract. Male butterflies of the species Heliconius melpomene produce an antiaphrodisiac pheromone during copulation (Schulz et al. 2008). This pheromone prevents the female from re-mating by repelling would-be mates.
Endogenous Transdermal Gifts: An endogenous transdermal gift is a gift that is created by the giver and injected into the skin of the receiver. In some species, male squids are known to inject their spermatophores into the tissue of the female (Hoving and Laptikhovsky 2007). The spermatophore releases a structure known as a spermatangium, essentially sperm encased in a thin covering.
Effects on Fitness
More often than not, nuptial gifts increase the reproductive fitness of the giver (Lewis and South 2012). This increase in fitness is not universal to receivers. Certainly, some receivers do increase in reproductive fitness after receiving a nuptial gift. Gifts can positively contribute to the size and number of eggs produced by a female, as well as the overall lifespan of that female (Lewis and South 2012). The longer a receiver lives, the more healthy offspring they can produce, leading to an increase in fitness. However, some nuptial gifts decrease the reproductive fitness of the receiver (Lewis and South 2012). Male fruit flies (Drosophila melanogaster) prevent females from re-mating through use of a mating plug (Bretman et al. 2009). These mating plugs physically block a female’s reproductive tract, with the purpose of retaining sperm. Mating plugs also prevent the females from re-mating, resulting in greater reproductive fitness for the male, allowing only his sperm to fertilize the eggs. This increase in fitness is not shared by the female, however; because she cannot re-mate, she incurs a loss in reproductive fitness.
The nursery web spider (Pisaura mirabilis) illustrates another form of nuptial gift that does not improve the reproductive fitness of the receiver (Ghislandi et al. 2014). Males in this species create nuptial gifts by wrapping insect prey in silk. However, male nursery web spiders have been known to deceive females by wrapping useless gifts, such as empty exoskeletons or plant materials. Whereas this behavior increases the reproductive fitness of the male without requiring a large degree of effort, the female is left without the nutritional content promised by the false nuptial gift.
The need to pass on genetic material has led to many unique strategies to ensure reproduction. Nuptial gifts vary incredibly between the many species they occur in; they can be oral or genital, made by the organism or found by the organism, and can be beneficial or detrimental to the fitness of the receiver. Despite this variance, nuptial gifts share a common trait of an increase in the reproductive fitness of the giver.
- Lewis, S., & South, A. (2012). The evolution of animal nuptial gifts. Advances in the Study of Behavior, 44, 53–97. https://doi.org/10.1016/B978-0-12-394288-3.00002-2.CrossRefGoogle Scholar