Owen D. Seeman

FEMALE BIASED PARASITISM AND THE IMPORTANCE OF HOST GENERATION OVERLAP IN A SEXUALLY TRANSMITTED PARASITE OF BEETLES

Sexual transmission is a widespread means of infection, but apart from those in humans, the ecology of sexually transmitted organisms is not well known. In this study, we present an ecological study of a sexually transmitted mite, Parobia husbandi Seeman and Nahrung (Acari: Podapolipidae), that lives beneath the elytra of Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae). In each of 2 yr, prevalence of mites on beetles began each spring at about 10–20% but gradually increased to 80–100% by late summer. Overlap of adult beetle generations at this time (i.e., the parental generation mating with the F1 generation) is essential for the persistence of these mites. Mites exhibited temporal change in their spatial distribution on beetles; these changes were probably a response to beetle activity (e.g., emergence from diapause) and the need for dispersal from parental to F1 generation beetles. Prevalence and mean intensity of mites was higher on female beetles compared with male beetles. Female bias of sexually transmitted infection has been predicted in animals but hitherto observed only in primates. We speculate that variable male mate-finding success is the cause of these sex-based differences of mite infections, and that female bias in sexually transmitted disease (STD) infection will be widespread in the animal kingdom.

A new species of Aegyptobia (Acari: Tenuipalpidae) from Myrtaceae in Australia

Abstract Aegyptobia yertle sp. nov. from Calytrix fraseri is described from adult females, deutonymphs and protonymphs. The palp and leg chaetotaxy is presented and reviewed for an additional 31 species of Aegyptobia. Of these species, 15 have a palp and leg chaetotaxy identical to A. yertle sp. nov. Amongst the remaining 16 species, there are 17 different variable setae. Within Aegyptobia, the greatest number of setae lost by any one species is eight. These results show that leg chaetotaxy is an informative addition to descriptions in the Tenuipalpidae. With respect to Aegyptobia, we suggest that leg chaetotaxy could help subdivide this large genus.

New Parobia (Acari: Podapolipidae) parasitic on pestiferous paropsine beetles (Coleoptera: Chrysomelidae) in eucalypt plantations.

Abstract Chrysophtharta cloelia (Chapuis), C. variicollis (Chapuis) and Paropsis atomaria Olivier are pests of plantation eucalypts in eastern Australia. Each of these species were infested with podapolipid mites (Acari: Podapolipidae), a group of mainly sexually-transmitted parasites often found beneath the elytra of beetles. C. cloelia and C. variicollis were host to one species, Parobia captivus sp. nov., that closely resembles Parobia husbandi Seeman & Nahrung 2003. In contrast, Ps. atomaria was host to three species, Parobia alipilus sp. nov., Parobia gimlii sp. nov. and Parobia lawsoni sp. nov. We re-diagnose Parobia and make changes to the setal nomenclature presented for the type species P. husbandi.

Ultrastructure of the male chelicerae of hattena cometis domrow (Acari: Gamasida: Ameroseiidae) functioning as gonopods

The ultrastructure and functional adaptations of male chelicerae in Hattena cometis Domrow are discussed. In particular, as in many other gamasid mites, males of Hattena use the chelicerae, modified as gonopods, to transfer the sperm into the female. For such purpose, a slender process extending from the movable digit, the spermatodactyl, is mainly involved. The spermatodactyl is provided with a sperm transfer duct; in H.cometis, the dorsal surface bent and fused with the ventral surface forms this duct so that the spermatodactyl appears as a cuticular process, connected somehow with the movable digit, and folded on itself to delimit the sperm transfer tube. The organization and ultrastructure of the spermatodactyl are discussed and compared with other gamasid mites studied so far. J. Morphol., 2013.

Ultrastructure investigation of the secondary insemination system of the gamasid mite Hattena cometis domrow (Acari: Anactinotrichida: Ameroseiidae).

Many gamasid mites, mainly of the taxon Dermanyssina, possess a secondarily evolved insemination system that is generally described as occurring in two types, the laelapid and the phytoseiid‐type, which are structurally considerably different. Considering that Dermanyssina represent the most recent and most diverse group of gamasid mites, it was expected that a greater diversity of insemination system than reflected by the two types could be present and could give an idea of its evolution within the taxon. Here, the authors present a description of the fine‐structure of the female secondary insemination system in the dermanyssine mite Hattena cometis. The system consists of a pair of sperm induction pores (solenostomes) and short sperm access ducts (tubules) which end in a syncytium. The syncytial strands of both sides meet medially under the ovary s.str., where they form a spherical syncytial spermatheca. Mature sperm cells of a modified ribbon type were seen in the syncytial parts of the system. The insemination system of Hattena cometis is regarded as a modification of the laelapid type. However, it is much simpler than that of Varroa destructor, the only other gamasid mite with the laelapid type studied ultrastructurally until now, and shows also some structural differences (e.g., no presence of an unpaired sperm duct). Hence, the present study suggests that some intermediate types might be revealed in future ultrastructure studies representing steps in the evolution of the insemination system in the Dermanyssina. J. Morphol. 274:918–925, 2013.

A new species of Tenuipalpus Donnadieu (Acari: Tenuipalpidae) from Iran

Abstract Tenuipalpus zahirii Khanjani & Seeman sp. nov., collected from leaves of hawthorn trees, Crataegus monogyna Jacq. (Rosaceae), and oleaster trees, Elaeagnus angustifolia L. (Elaeagnaceae), is illustrated and described from Simin, Hamedan Province, Iran. This species is the first member of the Tenuipalpus proteae species group from Iran. A key to all known Iranian species is provided.

Megisthanus leviathanicus sp. nov. (Parasitiformes: Megisthanidae), the largest known Mesostigmata, a symbiont of the beetle Mastachilus australasicus (Coleoptera: Passalidae)

ABSTRACT Megisthanus leviathanicus sp. nov. is described from the passalid beetle Mastachilus australasicus from Australia. The adult male is the largest of all known Mesostigmata with one specimen measuring 5.05 mm in length. The sexes are dimorphic: female mites are smaller, have numerous elongate setae, and a lyriform dorsal shield, while the major males have minute dorsal setae and a subovate dorsal shield. Some minor males (n = 4/48) resemble the female in having numerous elongate dorsal setae. Usually only one major male was found on a beetle, but rarely a minor male also occurred, suggesting that a major male defends a beetle and that minor males share access to females. Both sexes had considerable variation in the secondary sclerotization around their dorsal shields. This variation requires some adjustments to the current taxonomy. Herein Megisthanus caudatus is considered a senior synonym of M. brachyurus syn. nov. and M. testudo syn. nov., as M. brachyurus is based on a female without secondary sclerotization and M. testudo on the male of M. caudatus. The Australian species Megisthanus thorelli, and the North American species Megisthanus floridanus, are diagnosed. The diagnostic character states for megisthanid species are explored, especially the female’s internal genitalia. http://www.zoobank.org/urn:lsid:zoobank.org:pub:FB6B6509-64A6-4454-8B58-F412FA2833C1

Three new species of Eutarsopolipus (Acari: Podapolipidae) from Australian carabid beetles (Coleoptera: Carabidae)

Abstract Three new species of Eutarsopolipus Berlese, 1913 (Acari: Podapolipidae) are described from adult females, larviform adult males and larval females collected from under the elytra of pterostichine carabid beetles (Coleoptera: Carabidae) in southeast Queensland: Eutarsopolipus earnshawi sp. nov. from Cratoferonia phylarchus (Sloane, 1900), Eutarsopolipus lambkinae sp. nov. from Notonomus angustibasis Sloane, 1902 and Eutarsopolipus rutherfordae sp. nov. from Trichosternus subvirens (Chaudoir, 1865). All the new species belong to the ochoai species group and a key to species of this group is provided.

Ultrastructure of the Male Genital Tract, Spermatogenesis and Spermatozoa of Hattena cometis Domrow (Acari: Gamasida: Ameroseiidae)

The ameroseiid mite Hattena cometis has a male genital system that consists of an unpaired, u‐shaped testis and paired deferent ducts leading into an unpaired accessory genital gland and ejaculatory duct. The genital opening is located anteriorly immediately in front of the sternal shield. Spermatogenesis is simple, probably due to the haploid nature of the male. Eight stages of spermatogenesis could be roughly distinguished. Mature spermatozoa as found in the deferent duct lumen are peculiar in having a bisected nucleus and numerous peripheral flat chambers, which were formed from indentations of the plasmalemma. In inseminated females, spermatozoa were observed in the syncytial tissue of the sperm access system and in the somatic cells of the ovary. These spermatozoa have achieved a new structure, i.e., an electron‐dense plate dividing the cell into two unequal halves. The dense plate has an intricate substructure. Its function is unknown. These sperm cells are considered to represent capacitated spermatozoa. The peripheral chambers are reduced in number inside the female. Similar sperm cells, containing a dense plate, were seen in vacuoles within the epithelium of the deferent duct of one male. These cells are evidently under destruction, but before being completely dissolved had undergone a development leading beyond that of the mature sperm cells found in the deferent duct. Apparently, entering the cell of the deferent duct epithelium or the syncytium tissue triggers the production of the dense plate (or the capacitation process). Our observations are compared with results obtained from other anactinotrichid Acari, mainly Gamasida, and confirm and complete the interpretation of the correlated evolution of components of gamasid reproductive systems. J. Morphol. 274:1010–1025, 2013.

Precopula and female-biased sex ratio in Iphiolaelaps Womersley (Acari: Mesostigmata: Iphiopsidae)

are Womersley’s (1956) description of an adult male and female collected from “millipedes from Mt Lamington, Queensland, December 1948”, and those reported by Seeman & Nahrung (2000). These mites, however, can be collected readily from paradoxosomatid millipedes (Myriapoda: Polydesmida). The host species in the cover photograph is either