Animal Biology · Intermediate

Let’s not beetle around the bush – which parent does the better job?

There is no question that parents influence their children’s traits and characteristics. But have you ever wondered which parent affects you more – your mother or your father?
Research on a species, Nicrophorus vespilloides, shown in figure 1, has shown how different genders of grandparent and parent beetles have varying effects on offspring generations. It is suggested that youngsters brought up by females have improved qualities than those brought up by males. In an experiment by University of Southampton researcher Judith Lock, offspring were brought up by either their mother or father, and characteristics were measured to decide which parent provided better care. The traits measured were weight gain, time taken for the offspring to move away from the parent, and time taken for the beetles to go through the life stage larva to pupa, a process known as pupation.

Figure 1 [1]. A Nicrophorus vespilloides beetle. These beetles are brought up by both parents, so are the perfect models for research into how the gender of the parent as the sole carer can affect the offspring.
The experiment [2] began with a parental generation, P1. A pair of beetles from P1 were placed in an enclosure with a mouse carcass inside. The mouse carcass attracted both the male and female as these beetles are carnivorous [3], and allowed them to meet and mate together. Carcasses also provide an ideal home for the larvae that hatch from the eggs produced. One of the parents was selected to look after the offspring, and the parent and larvae were left until the larvae had moved away from the carcass. This marked the end of the relationship between the parent and offspring. This process was repeated, with the other parent providing care for the offspring instead. This process was later replicated with the offspring generation known as the F1 generation. The offspring generation of F1 is called the F2 generation. The layout of the experiment is shown in figure 2.

Figure 2 [2]. A diagram to show the structure of the beetle family. The research found that grandchildren in the F2 generation who were cared for by the mother, and the mother was cared for by their own mother, had the most valued traits.
The research found that parental gender had no effect on the F1 population; between parents, there was little difference between the three traits that were measured [2]. This is consistent with other findings, where beetle offspring do not discriminate between either parent [4]. However, grandparental gender and parental gender did influence the traits for the F2 generation. The offspring with the largest mass gain and longest pupation duration received care from the mother, and that mother received care from her own mother [2]. Those whose grandfather looked after their parent had a longer wandering time.

There is natural variation in how mothers and fathers nurture their offspring. Typically, mothers provide direct care to the offspring, whereas fathers provide indirect care by offering things such as food and shelter to the offspring. This behaviour can be seen in human families – historically, the father is the breadwinner, while the mother tends to stay at home looking after the children. This has been the social norm for decades, but gender roles are changing – women are more likely in our current society to be bringing home the bacon, leading to an increased number of stay-at-home dads or a more equal spreading of labour and childcare between parents. This provides a biologically controversial perspective, as in most species the female is the direct primary carer of the offspring, while the male is the indirect carer. The research spoken about above offers proof that the direct care mothers provide is more beneficial to the offspring’s development than the indirect care that fathers provide [2].


[1] (Accessed: 3 November 2016).

[2] Lock, J.E. (2011) ‘Transgenerational effects of parent and grandparent gender on offspring development in a biparental beetle species’, Biology Letters, 8(3), pp. 408–411. doi: 10.1098/rsbl.2011.0920.

[3] Ulyshen, M. (2004) ‘Diversity and seasonal activity of carrion beetles (Coleoptera: Silphidae) in northeastern Georgia’, JOURNAL OF ENTOMOLOGICAL SCIENCE, 39(3), pp. 460–463.

[4] Mäenpää, M.I. (2015) ‘Burying beetle larvae discriminate between individual parents and between some classes of adults’, Ethology, 121(4), pp. 395–402. doi: 10.1111/eth.12348.

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