The genus Aglaoapis is distributed in Europe, the Middle East, India and South Africa. Three species are known worldwide (Michener 2007), and only one species occurs in Europe (Ghisbain et al. 2023).

Larger species (9–12 mm), both sexes are black with well-developed white bands of short hair on metasomal terga (Fig. 1A, B). Both sexes have the fore coxa with a carina anteriorly (Fig. 1E) and a short projection and the scutellum with a medial toothlike projection (Fig. 1C). Females have a longer last tergum than females of the genus Dioxys and an emarginated last sternum (Fig. 1D). The last tergum is emarginated for males (Fig. 1F).

Aglaoapis tridentata is a Palaearctic species that occurs in Europe, from Spain in the west to Russia in the east (Fig. 2), and in Asia from the Caucasus, Kyrgyzstan and China, Kazakhstan, Siberia and Russian Far East. This species reaches the farthest north of any species of the tribe, with records from Finland and Sweden (Ornosa et al. 2008; Madsen and Calabuig 2010; Ascher and Pickering 2023).

Figure 2. 

Aglaoapis tridentata, distribution in Europe.

Biology and hosts: Species recorded especially in steppic formations, sunny slopes, forest steppes and other open or semiopen habitats. Occurs also in abandoned sandpits, spoil heaps and other habitats of anthropogenic origin. This species attacks nests of bees of the family Megachilidae, especially those nesting underground or making their own nests near the ground surface. Hoplitis anthocopoides (Schenck), Hoplitis ravouxi (Pérez), probably also Hoplitis adunca (Panzer) and Megachile pilidens Alfken, in southern parts of Europe, and also Chalicodoma parietina (Geoffroy) were confirmed as hosts of this species (Westrich 2018). Scheuchl and Willner (2016) also listed Megachile leachella Curtis as a likely host.

Nieto et al. (2014) classified this species as LC – data deficient. This species is relatively rare throughout its range. Its distribution in Europe is the largest of any species, and it is still being recorded in most countries – it was reported to be regionally extinct only in Belgium and Finland (Ghisbain et al. 2023). It should therefore be classified as LC.

Dioxys is a Holarctic genus distributed in most of Europe and North Africa to central Asia in the east and the southwestern USA and adjacent Mexico in the western hemisphere (Hurd 1958; Michener 2007). Five species occur in North America, and approximately 13 occur in the Palaearctic region (Warncke 1977; Ghisbain et al. 2023). Six species occur in Europe.

Larger species, body length 8–10 mm. In both sexes, typical in its colouration, the metasoma is completely reddish without terminal or basal bands, and the legs and flagellum are reddish (Fig. 3A, B). T6 of females is elongated and narrowed posteriorly, with a rounded apex. The mesosoma is ferruginously hirsute. Axillae with teeth and postscutellum with short but sharp tooth in the middle. The same characteristics are also typical for males.

Figure 3. 

Dioxys ardens A female, dorsal view B male, dorsal view.

Spain, Portugal (Fig. 4) and North Africa (Morocco to Libya).

Figure 4. 

Dioxys ardens, distribution in Europe.

Species recorded from semideserts and other arid open habitats. Hosts unknown.

This species is known only from several records from southern parts of Spain and one record from Portugal. Nieto et al. (2014) listed this species as DD – data deficient. According to the distribution records, it can be VU-vulnerable because of its long-lasting rarity. However, we know only a little about the populations and occurrence of this species in recent years.

In general, a similar species, Dioxys chalicoda Lucas, was recorded from North Africa (Algeria and Libya). One very old record is from Gibraltar, but this specimen was erroneously identified and belongs to D. ardens (coll. Biologiezentrum Linz, Austria). This species differs in the colouration of the metasoma, which has black colouration of at least the last three segments. Females have mandibles with lateral tubercles, and males have ends of S4 with an emargination and S5 and S6 convex.

This species is small (5–7 mm in total length) and completely black with well-developed apical bands on metasomal terga (Fig. 5A, B). It is generally similar to Dioxys lanzarotensis, from which it can be identified by denser punctation on metasomal terga (Fig. 5C) and clypeus. It is morphologically similar to D. moestus, which is probably its near relative, rather than to D. cinctus, into which it was previously classified as a subspecies (Warncke 1977). The dark colouration of tibial spurs reported by Warncke (1977) was not observed in any specimen I have studied (Fig. 5D). Based on the morphology and distribution, it is clearly a separate species. Syntypes (a male and a female from Santa Cruz, Tenerife) from the Natural History Museum London were studied.

Figure 5. 

Dioxys atlanticus A female, dorsal view B male, dorsal view C female, mesosoma dorsal view D female, tibial spur on fore leg E male, last metasomal segments, ventral view. Red scale bars represent the length of 1 mm, blue scale bars 100 µm.

This species was described from a male and a female from the Canary Islands (Tenerife), where it was also recorded on two other islands – Lanzarote and Gran Canaria (Hohmann et al. 1993) (Fig. 6). It was also recorded in Egypt (Warncke 1977) and currently in Sardinia (Orroli, 02.vi.2011, 6 ♀♀, G. Pagliano lgt., P. Bogusch det., coll. Biologiezentrum Linz, Austria). Based on the records, the species occurs in the Canary Islands and several parts of North Africa, South Europe and perhaps the Middle East, but it is very rare and hard to find. Specimens from Sardinia correspond in size, morphology and colouration with those of the Canary Islands and with both syntypes.

Figure 6. 

Dioxys atlanticus, distribution in Canary Islands.

The species occurs in open habitats – steppes, semideserts, in rocky areas with shrubby vegetation. Little is known about its biology. Hosts unknown.

Conservation status: Nieto et al. (2014) listed this species as DD – data deficient. There are quite recent records from the Canary Islands and new records from Sardinia (Italy). In my opinion, it should be VU – vulnerable because of its restricted distribution area.

Type specimens of this species and the description were studied in Biologiezentrum Linz, Austria. Both type specimens (a male and a female from the Sertavul Pass in Turkey) do not morphologically differ from typical specimens of D. cinctus.

Larger species, body length variable between 5–12 mm, probably depending on the host. In both sexes, the body is black with the first two metasomal terga entirely or partly reddish and narrow apical bands of whitish short appressed hair (Fig. 7A, B). In several cases, red colouration is present on T3–T4. Mesosoma bears long whitish hair, apex of T6 of females straight and only shortly elongated, shorter than in similar species (Fig. 7D). The legs and antennae are black. This species has a very large distribution area and is connected with many host species. It causes variability in size (5–12 mm), while populations from southern Europe and North Africa are often smaller. The colouration is very variable, too – normally both sexes have first metasomal terga entirely reddish but usually populations from the north of the distribution area are darker and sometimes are entirely black with no reddish pattern.

Figure 7. 

Dioxys cinctus A female, dorsal view B male, dorsal view C female, fore coxa D female, mesosoma dorsal view E male, last metasomal segments, ventral view F male, T4–T6, dorsal view. Red scale bars represent the length of 1 mm.

A species with a western Palaearctic distribution known from central and southern Europe from Portugal to Greece and Romania (Fig. 8). Outside of Europe, it is found in North Africa, Israel and as far east as the Caucasus (Dusmet 1921; Popov 1936; Warncke 1977; Standfuss et al. 2003; Ornosa et al. 2008; Ascher and Pickering 2023).

Figure 8. 

Dioxys cinctus, distribution in Europe.

Species occurring in a variety of open and semi-open habitats: steppe, semideserts, forest steppes and many others. It was also recorded in sites of anthropogenic origin – former sandpits, quarries, spoil heaps and military exercising areas. This species has more host species in its large distribution area: Chalicodoma parietina, Chalicodoma pyrenaica Lepeletier, Hoplitis adunca and Hoplitis anthocopoides were confirmed (Scheuchl and Willner 2016). Its hosts nest underground, create nests of mud or resin, or nest in various types of cavities above the ground. Parasitising females of this species were often recorded around bee hotels associated with nests of H. adunca in the Czech Republic (P. Bogusch, unpublished records). The actual number of hosts is certainly higher, and the preferred host species differ among the localities within the large distribution area.

Nieto et al. (2014) classified this species as LC – least concern. It is distributed in most of southern and central Europe, with the northern distribution border in France, Germany, the Czech Republic and Ukraine. In many countries, it is not rare, and the numbers of recorded individuals are even higher than those of A. tridentata. In the Czech Republic, the species has spread in the last 20 years (Straka and Bogusch 2017). Thus, it should stay in the category LC.

Small species very similar in morphology to D. atlanticus (Fig. 9A) but differs by sparser punctures on metasomal terga (Fig. 9B) and on clypeus. Only a single male (holotype) was recorded from the island Lanzarote of the Canary Islands (Spain) (Tkalcu 2001). The holotype should be deposited in Übersee-Museum Bremen, Germany, but was discovered in the collection of Francisco La Roche in San Cristóbal de La Laguna, Tenerife, Spain. According to the studies of the holotype, this species is very similar to males of D. atlanticus but differs by the above reported characteristics, as well as several others (length and position of toothlike processes on S4 (Fig. 9D), shape of head). It is certainly a separate species; however, its distribution area is restricted to one island.

Figure 9. 

Dioxys lanzarotensis A male, dorsal view B male, metasoma, dorsal view C male, mesosoma dorsal view D male, last metasomal segments, ventral view. Red scale bars represent the length of 1 mm.

Lanzarote, Canary Islands, Spain (Fig. 10) (Tkalcu 2001).

Figure 10. 

Dioxys lanzarotensis, distribution in Canary Islands.

Unknown.

Nieto et al. (2014) classified this species as DD – data deficient. It is the only category in which this species can be classified because we know only one specimen, the type.

Middle-sized species, body length 5–8 mm. Species with typical general appearance for this genus, black with first 2–3 metasomal terga entirely or partly reddish, with narrow apical bands of whitish short appressed hair (Fig. 11A, B). Mesosoma with long whitish hair, apex of metasomal T6 rounded (Fig. 11C). The legs and antennae are black. The last metasomal terga in males was not as narrow as that in D. cinctus. In general, similar to D. cinctus but differs by several characteristics: it is usually smaller and the reddish colouration is more distributed (usually on T1–3, in D. cinctus on T1–T2). Females of D. cinctus have a straight apex of T6, while females of D. moestus have a round apex of T6. Males of D. moestus have two tooth-like processes on S4 medio-posteriorly (Fig. 11F), and males of D. cinctus lack this characteristic. Punctation of T2–T3 of D. moestus is finer and sparser than in D. cinctus.

Figure 11. 

Dioxys moestus A female, dorsal view B male, dorsal view C female, mesosoma dorsal view D female, metasoma, dorsal view E female, metasoma lateral F male, last metasomal segments, ventral view G male, T4–T6, dorsal view. Red scale bars represent the length of 1 mm, blue scale bars 100 µm.

Mediterranean species described from Sardinia. Recorded from Portugal to Greece (Fig. 12). Outside of Europe, it is recorded in North Africa, from Morocco to Tunisia, and Israel (Warncke 1977; Ornosa et al. 2008).

Figure 12. 

Dioxys moestus, distribution in Europe.

This species occurs in open habitats. It was collected in open habitats with shrubby vegetation, steppic formations or rocky landscapes with almond orchards. Hosts are Hoplitis benoisti (Alfken), Hoplitis fertoni (Pérez) and Hoplitis zandeni (Teunissen & van Achterberg) (Bogusch et al. 2020b), probably also Hoplitis ochraceicornis (Ferton) (I. Cross, unpublished record). Several specimens were reared from nests of H. fertoni placed inside snail shells (Bogusch et al. 2020b).

Nieto et al. (2014) classified this species as DD – data deficient. This species occurs in most of southern Europe, where it is rare but still frequently recorded. It can be classified as LC – least concern.

Dioxys heinrichi Warncke occurs in North Africa (Morocco and Algeria) and is similar to D. moestus. Female D. heinrichi have a longer F2 and more convex clypeus, and males do not have a swollen end of S4 and lack the two small teeth. The end of S5 is slightly emarginated.

Smaller species, total body length 4–6 mm. Species with typical general appearance for this genus, black with first 2–4 metasomal terga entirely or partly reddish, with narrow apical bands of whitish short appressed hair (Fig. 13A, B). Mesosoma with long whitish hair, apex of metasomal T6 rounded (Fig. 13C). The legs and antennae are at least partly reddish. Last metasomal terga in males not as narrowned as in D. cinctus, last tergum more curved than in D. moestus and D. cinctus. Species in general similar to smaller individuals of D. moestus and D. cinctus differ by reddish legs and flagellum. Females have a T6 that is longer than it is wide (distinctly longer than the T6 of both similar species), males do not have a sharp medio-posterior projection on S4 (present in D. moestus) but the apex of S4 is waved, not straight as in D. cinctus (Fig. 13E). Punctation of T2–T3 is coarser and denser than in D. moestus and D. cinctus. Specimens from Cyprus (described by Popov, 1944 as a separate species) look Smore colourful at first view but do not differ in their morphology, and the diagnostic characteristics of D. cypriaca are variable and form a continuous line to D. pumilus. Thus, D. cypriaca is currently supposed to be a synonym of D. pumilus.

Figure 13. 

Dioxys pumilus A female, dorsal view B male, dorsal view C female, metasoma, dorsal view D female, metasoma lateral E male, last metasomal segments, ventral view F male, last metasomal segments, dorsal view. Red scale bars represent the length of 1 mm.

This is a western Palaearctic species. The nominate subspecies occurs in the eastern Mediterranean basin (Greece, Cyprus, Turkey) (Fig. 14) and spreads towards Asia Minor (Israel, Syria) and Iran. The subspecies D. p. varipes occurs in the western Mediterranean basin (Sicily, Spain, Morocco, Algeria, Tunisia). The taxonomic statuses of these subspecies are unclear, but they do not differ in morphology, other than the specimens from western parts of the distribution area often being darker than those from the east.

Figure 14. 

Dioxys pumilus, distribution in Europe.

This species was recorded in a variety of open and semi-open habitats – steppes, forest steppes, semideserts, open landscapes with shrubby vegetation and many others. Heriades crenulatus Nylander was reported as a likely host of this species in Cyprus (Mavromoustakis 1959). In Portugal, it was recorded in association with Hoplitis annulata Latreille (Baldock et al. 2018). Small species of Osmiini are also supposed to be host species of D. pumilus.

Nieto et al. (2014) classified this species as DD – data deficient. This species occurs in many countries in southern Europe, while in several localities, it has been recorded in large series. It is more local than D. moestus but probably more numerous at the localities. It can be classified as LC – least concern.

This genus is distributed in North Africa and the Middle East, from Morocco in the west to Turkmenistan in the east. Three species were described, one of which was reported from Europe – Portugal and Spain (Popov 1936, 1953; Michener 2007).

Larger species, body length 7–10 mm. The only species of the genus recorded from Europe. It is typical by the characteristics of the genus; both sexes are generally similar to Dioxys species (Fig. 15A, B) but lack axillar teeth (Fig. 15C). T5 of females is shiny, and T6 and S6 are elongated with two lateral teeth, similar to Paradioxys pannonica (Fig. 15D). P. pannonica differs in the black or dark brown colour of the entire body, with a reddish pattern only on the first three metasomal terga and distinct apical bands of whitish short appressed hair on the metasomal terga.

Figure 15. 

Ensliniana bidentata A female, dorsal view B male, dorsal view C female, last metasomal segments, dorsal view D female, mesosoma, dorsal view E male, last metasomal segments, dorsal view. Red scale bars represent the length of 1 mm.

In Europe, only several specimens are known from Spain and Portugal (Ornosa and Ortiz-Sánchéz 2014; Torres 2020; Ascher and Pickering 2023) (Fig. 16). It was described from Israel (Jericho and Oran). Outside of Europe, it is known from Morocco, Algeria, Tunisia, Turkey, Syria, Israel and Jordan (Grace 2010).

Figure 16. 

Ensliniana bidentata, distribution in Europe.

This species probably occurs in open habitats – steppic grasslands, rocky slopes, semideserts and other habitats. Baldock et al. (2018) listed Hoplitis zaianorum (Benoist) as a likely host of this species.

Nieto et al. (2014) classified this species as DD – data deficient. This species is known in Europe only from Spain and Portugal, where it was recorded both in the past and in recent years. It can be classified as VU – vulnerable because of its restricted distribution area in Europe.

This genus has a similar distribution to the previous genera in North Africa and the Middle East, from Morocco in the west to Uzbekistan in the east. Three species were described, one of which was reported from Europe – Greece (Popov 1936, 1953; Michener 2007).

Larger species, body length 8–10 mm. Species generally very similar to those of the genus Dioxys, black with first 2–4 metasomal terga entirely or partly reddish (rarely whole metasoma reddish and other body parts reddish), with narrow apical bands of whitish short appressed hair (Fig. 17A, B). Whole body with scale-like whitish short appressed hair, similar to those of Epeolus species. Apex of metasomal T6 more elongated than in Dioxys and Aglaoapis, rounded (Fig. 17D). The legs and antennae are at least partly reddish. Typical with sharp carina on coxa of front leg laterally, postscutellum without teeth medioapically, only with an ill-visible tubercle (Fig. 17C). In both sexes, T6 was without emargination (Fig. 17D, E).

Figure 17. 

Metadioxys graeca A female, dorsal view B male, dorsal view C female, mesosoma dorsal view D female, metasoma, dorsal view E male, last metasomal segments, dorsal view. Red scale bars represent the length of 1 mm.

In the European region, this species is known from Greece (Thessaly and Crete) (Fig. 18). Its range extends out of the European region to Asiatic Turkey, Morocco and Israel (Warncke 1977; Grace 2010; Ascher and Pickering 2023; Kuhlmann et al. 2023).

Figure 18. 

Metadioxys graeca, distribution in Europe. Doubtful record from Italy in orange.

This species probably occurs in open habitats – steppic grasslands, rocky slopes, semideserts and other habitats. Hosts unknown.

Nieto et al. (2014) classified this species as DD – data deficient. There are only old records from Greece and one doubtful record from Italy (certainly this species but probably wrongly labelled), and no recent finds are known. Because of its unknown population trend, we must leave this species in category DD – data deficient.

Metadioxys formosa Morawitz occurs in North Africa (Morocco) and the Middle East (Israel and Turkmenistan). It is smaller than M. graeca (6–8 mm), and both sexes have scale-like whitish short appressed hair distributed on more parts of the body than M. graeca. Female has last tergum broadened laterally; male has deeply emarginated last sternite.

This genus is reported from southeastern Europe and the Middle East. Its occurrence ranges from Austria in the west to Iran in the east. Two species are known, one of which occurs in Europe (Popov 1936; Michener 2007).

Middle-sized species, body length 7–10 mm. The only species of the genus within Europe. Typical by the characteristics of the genus, similar to species of the genus Dioxys. It is uniform in appearance, females black with first four metasomal terga entirely reddish amd males’ whole metasoma reddish. Legs are also reddish (Fig. 19A, B). Metasoma of females have narrow apical bands of whitish short appressed hair; similar hairs are also distributed on the first metasomal terga laterally. The metasoma of males have bands of whitish short appressed hair that are sparse and barely visible. The male body has a tomentum-like light brown or yellowish hair. Females have a narrowed T6 and a very long and sharp S6, projecting behind the T6 (Fig. 19C). In males, the end of the metasoma is straight, not curved (Fig. 19F), and the apex of S4 has two prominent toothlike projections, which are larger than in males of Dioxys (Fig. 19D, E).

Figure 19. 

Paradioxys pannonicus A female, dorsal view B male, dorsal view C female, last metasomal segments, dorsal view D male, metasoma, ventral view E male, last metasomal segments, ventral view F male, last metasomal segments, dorsal view. Red scale bars represent the length of 1 mm, blue scale bars 100 µm.

This species was described from Hungary and is a Euro-Asiatic species that occurs from central Europe to the north-eastern Mediterranean (Fig. 20) and outside of Europe towards the Middle East and Iran (Popov 1936; Warncke 1977; Bogusch et al. 2007; Gusenleitner et al. 2012; Ascher and Pickering 2023).

Figure 20. 

Paradioxys pannonicus, distribution in Europe.

This species attacks nests of species of the family Megachilidae. Scheuchl and Willner (2016) reported Chalicodoma hungarica (Mocsáry) as its main host, and Gusenleitner et al. (2012) included C. parietina as its host.

Nieto et al. (2014) classified this species as DD – data deficient. This is a typical Pannonian species occurring in the Pannonian basin. However, there is a lack of records from recent years, and the most recent finds are from the 1970s and 1980s. We suppose this species is CR – critically endangered in Europe.