Table 1.

Independent origins of haplodiploidy and pseudo-haplodiploidy (PGE) among insects

Order/class	Haplodiploid clade	Type of haplodiploidy	Species number	No. of species data	Monophyletic?	Evidence of loss
Coleoptera	Micromalthus	Arrhenotoky	1	1	Yes	No
Coleoptera	Xyleborini	Arrhenotoky	1360	5	Yes	No
Coleoptera	Hypothenemus	PGE	179	1	Yes	?
Collembola	Symphypleona	PGE	1188	10	Yes	No
Diptera	Sciaridae + Cecidomyiidae	PGE	8468	32	Yes	?
Hemiptera	Aleyrodidae	Arrhenotoky	1550	4	Yes	No
Hemiptera	Iceryini	Arrhenotoky	81	12	Yes	Noa
Hemiptera	Neococcoidea	PGE	7000	400	Yes	Yes
Hymenoptera	Hymenoptera	Arrhenotoky	115000	1600	Yes	No
Phthirapterab	Phthiraptera	PGE	3000	15b	Yes	?
Thysanoptera	Thysanoptera	Arrhenotoky	5000	24	Yes	No

Each row shows an independent origin of haplodiploidy or PGE, describing the estimated size of the clade and the number of species for which we have data in our database. The “evidence of loss” column is based on the presence or absence of diplodiploid species within these clades.

^aNo reversion to diploploidy, but several origins of selfing hermaphroditism.

^bPGE per se has only been described in a single species, but cytogenetic data on 14 other species shows an unusual type of spermatogenesis that might be indicative of PGE across lice families.