Sperm (the thin green cells) from a human bedbug Cimex lectularis, swimming out of the female’s secondary set of genitalia (the round cells) into her body cavity on their way to the ovaries. Oh, evolution.

Sperm

Sperm (the thin green cells) from a human bedbug Cimex lectularis, swimming out of the female’s secondary set of genitalia (the round cells) into her body cavity on their way to the ovaries. Oh, evolution.

Sperm

My PhD research focused on the evolution of sperm morphology, especially in the obscura sub-genus of Drosophila. These ~55 species of fruitflies are fairly unusual, in that they have two discrete sperm morphs: one is longer and is capable of fertilisation, and the other is short and apparently never fertilises eggs. My PhD tried to figure out why the flies have evolved two types of sperm when most species do fine with just one. We found some evidence that the smaller sperm improve the survival of their larger brothers after mating, though I’d like to revisit this problem someday and figure it out once and for all!

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Luke Holman
Senior Lecturer

Publications

Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, …

As recently outlined in TREE [1], many animals and plants are thought to load their male gametes with multiple types of RNA, some of …

Sperm competition can produce fascinating adaptations with far‐reaching evolutionary consequences. Social taxa make particularly …

The causes and consequences of variation in sperm quality, survival and ageing are active areas of research in ecology and evolution. …

Many internally‐fertilizing animals produce seminal fluid which is transferred along with sperm during mating. Seminal fluid typically …

Spermicide (i.e., female-mediated sperm death) is an understudied but potentially widespread phenomenon that has important …

Sperm size and number are important determinants of male reproductive success. The genus Drosophila exhibits a remarkable diversity of …

Sperm competition and cryptic female choice profoundly affect sperm morphology, producing diversity within both species and …