Kinship and acquaintance for the benefit of offspring

The troops, retreating, burning and exploding fields, factories and bridges behind them, leaving nothing to the enemy. Males of some species adhere to the same strategies: after mating, they damage the reproductive paths of females so that they can not use competitors who claim to transfer their genes to the future generations. However, if the competitor is a close relative, who is also well familiar, and he will convey the genes not strangers, but family, that from an evolutionary point of view is not bad, then maybe the male will not cripple the female? This hypothesis was nominated by a professor at the University of West Australia Lee Simmons (Leigh W. Simmons) and his graduate student Samuel J. Lymbery. They managed to confirm it on a small beetle, a four -fifth grade Callosobruchus maculatus [1]. But about everything in more detail.

As you know, sexual relations are often accompanied by conflicts, since their participants pursue different goals. Although both sides are interested in the maximum number of descendants, it is very important for the male that only he is the manufacturer. Therefore, there are frequent cases when a male kills other people's cubs or cripples a partner to prevent her relationship with competitors. Samok, in turn, develop protective devices. So the sexual antagonistic coevolution flows.

As a rule, experts studying this process do not take into account the kinship of participants. If we consider each male as a loner, the selection must act on signs that enhance the individual reproductive success of the individual; The conflict of sexes and competition for the female are aggravated to extreme. If a group of males fertilizing one female is connected by related bonds, they all continue one genus and, therefore, the process of reproduction can be less traumatic.

Several years ago, specialists of Oxford University found the following feature in Drosophila [2]. One female was planted with three males not related to her. If these three were brothers, the female laid more eggs than after staying with males who are not related. In addition, the brothers fought with each other less often and lived longer. The importance of family ties was proved for Hetrandria Formosa fish [3].

However, such a result cannot be attributed exclusively belonging to one family group, since relatives usually grow nearby and know each other well, unlike outsiders, which are rare. Maybe it's not about related, but in acquaintance?

And a year later, scientists from Lausanne University (Switzerland) have proved that the conditions under which males grew extremely important for the relations of the sexes [4]. If the brothers-zofil was separated at the egg stage, then there was no benefit from their kinship from their kinship. The subsequent work performed at Drosophila Melanogaster with oxphone researchers showed that for the well -being of females it is important and the kinship of its sexual partners and their acquaintance with each other [5].

It would be strange to investigate the problem of sexual antagonistic evolution exclusively on Drusophila - the circle of species had to be expanded. Australian scientists, which were already discussed above, have chosen an interesting object - four -fifth grain C. Maculatus . On the penis of males of grain - spikes, and, the longer they are, the more offspring their owner leaves. Perhaps spikes help to extract the sperm of competitors from the reproductive tract, but they damage her fabrics. Such a rigid mating, preceded by the pursuit of a partner, reduces her life life and the total number of eggs that she puts off. The defense of the females is a dense connective tissue of the reproductive tract, the thickness of which depends on the size of male genitals in this population.

C. Maculatus is convenient to breed in the laboratory, because they do not know how to fly. The life of the beetle is limited by one pea. The female sticks the egg on its surface; The larva, hatching, bite under the shell, where it develops before puberty on the onset of puberty. Adult grains mate with the nearest neighbors.

At the University of Western Australia, the female C. Maculatus laid eggs on the seeds of cow peas Vigna Unguiculata . The researchers laid each pea in a separate test tube and, when beetles were born, brothers or non -treasured males planted three. After a day, part of the males was moved so that in one test tube there were brothers who had previously lived separately. In the same way they treated with non -treasured males.

As a result, scientists received four large groups of males: familiar relatives; unfamiliar relatives; non -native and unfamiliar; Non -native, but acquaintances. Each group had 54 three. Each three was transplanted to a large container, where the female was sitting for two days from the family - from the same generation, but not a relative to their partners - and were waiting for the eggs of 50 fresh peas. When the female was dying, scientists calculated the number of layered eggs and the number of viable offspring.

The results of the experiments are presented in the figure. It turned out that neither kinship nor acquaintance of males influenced the life expectancy of females. But when mating with familiar brothers, females postponed the maximum number of eggs, from which viable larvae hatched. Kinship, not backed up by personal acquaintance, did not have such an effect, as well as acquaintance in itself.

An important role of acquaintance at first glance seems strange. Males of the four -fifth grain, barely seeing the female, rush at her. If there are no living nearby, they try to master the dead (the authors of the work personally observed such a picture). Where is the rivals to look at! However, after mating, the beetles form a new sperm for the day and during this period they are incapable of fulfilling marital duties -maybe they use this time in order to look at the surrounding males. It was the day of beetles that three were kept in a test tube before letting them down to the female. But what can they see?

Cereals have no social hierarchy, so it does not make sense to first find out the status of competitors. However, since the effect of acquaintance was triggered only with related bonds, scientists suggested the existence of some signs of kinship that the males recognized when they had time for this. What kind of markers are it still to be found out; Perhaps - hydrocarbons of cuticles that have individual differences. It is possible that the males perceived acquaintance as an additional sign of kinship.

So, the Zernovka beetle considers not every male at all and, depending on the structure of the population, begins his destructive marriage behavior, not crippling a partner without evolutionary necessity. What exactly these behavioral changes were, scientists did not find out, limiting themselves to a general conclusion. In the future, they plan to deal with the mechanisms of recognition of relatives and find out how the behavior of beetles will change with a long change in the structure of the population.

Natalia Reznik

1. Lymbery SJ, Simmons LW Males Harm Females Less When Competing with Familiar Relatives // Proc. R. SOC. B. 2017. 284: 20171984. DOI: 10.1098/RSPB 2017.1984

2. Carazo P., Tan CKW, ALEN F., Wigby S., Pizzari T. Within-Group Male Reladures Harm to Females in Drosophila // Nature. 2014. 505. P. 672–675. Doi: 10.1038/Nature12949

3. Ala-Honkola O., Friman E, Lindstrom K. Costs and Benefits of Polyandry in a Placental Poeciliid Fish Hetorandria Formosa Are In Accordance withffspring Conflict Theory of Lacation // J. Evol. Biol. 2011. 24. P. 2600–2610. DOI: 10.1111/J.1420-9101.2011.02383.x

4. Hollis B., Kawecki TJ, Keller L. No Evidence that Within-Group Male Relatedness Harm to Females in Drosophila // Ecol. Evol. 2015. 5. P. 979–983. DOI: 10.1002/ECE3.1417

5. Le Page S., Sepil I., FLINTHAM E., Pizzari T., Carazo P., Wigby S. Male Relatedness and Familiarity Are Requered to Modulate Male-Induced Harm To Females in Drosophilaa // proc. R. SOC. B. 2017. 284. 20170441. DOI: 10.1098/RSPB 2017.0441