Psenini (Pate, 1946)

Genaro, Julio A., 2006, Checklist and distribution patterns of apoid wasps (Hymenoptera: Apoidea: Sphecidae and Crabronidae) of Cuba, Zootaxa 1171, pp. 47-68 : 57-63

Tribe Psenini

76. Pseneo garcesii Genaro and Alayo, 2001 . Cuba.

77. Pseneo collantes Genaro and Alayo, 2001 . Cuba.

78. Psen (Psen) venetus Pate, 1946 . Cuba.

79. Mimumesa longicornis (W. Fox, 1898) . = Psen floridana Rohwer, 1910 ; = Mimesa striatus Viereck, 1901 . North America ( Canada, New York to Florida, Louisiana, Iowa), Central America and Cuba.

80. Pluto arenivagus Krombein, 1950 . USA (Florida, Georgia and North Carolina) and Cuba. The subspecies P. arenivagus cubanus van Lith, 1979 occurs in Cuba.

81. Pluto argentifrons (Cresson, 1865) . Cuba, Jamaica, Mexico and Nicaragua.

Subfamily Philanthinae

Tribe Philanthini

82. Philanthus banabacoa Alayo, 1968 . Cuba.

Tribe Cercerini

83. Cerceris flavocostalis Cresson, 1865 . Cuba and Isla de la Juventud.

84. Cerceris triangulata Cresson, 1865 . = C. bilunata Cresson, 1865 . Cuba and Isla de la Juventud.

85. Cerceris trinitaria Alayo, 1968 . Cuba.

86. Cerceris festiva Cresson, 1865 . = C. gratiosa Schletterer, 1887 . Cuba and Isla de la Juventud.

87. Cerceris cubensis Cresson, 1865 . = C. zonata Cresson, 1865 . Cuba, Isla de la Juventud and Bahamas (San Salvador Island).

88. Cerceris hatuey Alayo, 1968 . Cuba.

89. Cerceris cerverae Giner­Marí, 1941 . Cuba.

Discussion

Origin and occupation of the Antilles

The islands of the Greater Antilles, as habitats with conditions proper to support terrestrial life, are not older than the Middle Eocene (~40 my) ( Iturralde­Vinent and MacPhee 1999, MacPhee and Iturralde­Vinent 2000, Penney 2005). Earlier islands must have existed, but due to repeated marine transgressions, subsidence and the K/T bolide impact and associated mega­tsunamis they were unlikely to be continuously subaerial (emerged) entities ( Iturralde­Vinent and MacPhee 1999). From the Eocene­Oligocene transition (35–33 ma) to the Middle Miocene (16 my–14 my) the subaerial exposure of land within the Caribbean basin was extensive. According to Iturralde­Vinent and MacPhee (1999) and MacPhee et al. (2003) a subaerial connection (whether continuous or punctuated by water gaps) called GAARlandia (Greater Antilles Ridge+Aves Ridge), connected Northwestern South America with larger land masses emergent on these ridges.

For these reasons, the West Indian terrestrial fauna is young. Amber deposits (from resin produced by the tree Hymenaea protera Poinar, Leguminosae ) in the Dominican Republic contain insect fossils of high quality. The amber is estimated to be 15–20 my of age ( Iturralde­Vinent and MacPhee 1996; Iturralde­Vinent 2001). Studies of the amber bees, ants and wasps suggest that the faunal representation is very similar to today’s fauna, and assignable to modern genera or to extinct genera closely related to present day ones ( Wilson 1985, 1988, Prentice and Poinar 1993, Engel 1995, 1997). Among the Dominican Republic amber ants, many genera became extinct and were substituted by others in later colonisations ( Wilson, 1985, 1988). The late Quaternary climatological changes (mean temperature and humity, rainfall and variations in mean sea level) ( Curtis et al. 2000, Iturralde­Vinent 2003) that affected the islands should also have affected the biota, including the wasps.

Ancestors of Cuban Sphecidae and Crabronidae originated outside of Cuba (in continental land masses) and dispersed to Cuba, through flight, or by wind (possibly hurricanes for the smaller ones like Oxybelus , Nitela , Stigmus ). Once the species were within the present vicinity of Cuba, vicariance events may have had an influence in the formation of the current faunas of each island, although dispersion may be acting always. Vicariance (island­island) may have occurred when Caribbean neotectonism resulted in the subdivision of existing land areas ( Iturralde­Vinent and MacPhee, 1999; MacPhee and Iturralde­Vinent, 2000), isolating populations of wasps that proceeded to evolve independently. For example, Cuba itself was composed of three separate large archipelagos in the Early Miocene ( MacPhee et al., 2003).

There are three dispersal routes by which the Proto­Antilles could have received fauna since the Middle Eocene ( Fig. 2 ): 1. From Florida (crossing the water gap between the neighbouring land masses; and, after the Bahamas emerged, by using them as stepping stone islands). 2. From Mesoamerica (from Yucatan, over the water gap from the close land mass; and by using the Nicaragua rise, in the late Oligocene­Middle Miocene by flight and use of stepping stones islands). 3. From Northern South America via GAARlandia, at the latest in the Eocene­Early Oligocene, by flight and use of stepping stone islands.

The power of dispersion of the wasps from one island to another can be demonstrated by the species on Mona (64 km ²) and Navassa (5.2 km²) Islands. Mona emerged much later (Pliocene or early Pleistocene) than the nearest lands that surround them (Smith et al 1994). Navassa was on its own tectonic plate and although its age as an emerged island is uncertain, it may have formed as a small coral atoll at the close of the Miocene Period about 5 million years ago, when these reefs began to emerge (W. Steiner and G. Alayón, pers. comm., 2006). Both oceanic islands entirely lacked any type of terrestrial connection ( Burne et al. 1974, Peck and Kukalova­Peck 1981; Smith et al 1994), but they contain elements of the fauna of their nearest islands (Mona Island to Puerto Rico (42 miles) and Hispaniola (37 miles), and Navassa Island to Cuba (100 miles), Jamaica (70 miles) and Hispaniola (35 miles).

Composition of the apoid wasp fauna of Cuba

The native fauna of apoid wasps of Cuba consists of 89 species, grouped in 36 genera and two families: Sphecidae (15 spp) and Crabronidae (74 spp). The Crabronidae is composed of Astatinae (1 sp), Bembicinae (15 spp), Crabroninae (41 spp), Pemphredoninae (9 spp) and Philanthinae (8 spp). The genera with the largest number of species (and their percentage endemism) are: Trypoxylon , 10 (50%); Liris , 8 (0%); Cerceris , 7 (85.7%); Hoplisoides , 5 (80%); Sphex , 5 (40%); Ectemnius , 5 (60%) and Tachysphex , 5 (0%). The families Heterogynaidae and Ampulicidae do not ocur in Cuba.

There are two continental genera, Trachypus and Chalybion , that do not occur in Cuba. Trachypus is present in Hispaniola and Puerto Rico, with one species ( T. gerstaeckeri Dewitz ). The species of Chalybion that lives in Hispaniola ( C. zimmermanni Dahlbom ) is distributed throughout most of the United States (except Florida and a few other states), Mexico to Costa Rica.

Cuba shares the largest number of species with Hispaniola and Jamaica (22%), and with the North American continental land mass (20 %, Fig. 2 ). The West Indian distribution of many species is patchy and uneven. Further sampling throughout the Bahamas, Hispaniola and the Lesser Antilles will likely prove that many of the Cuban species are more widely distributed, and that the Cuban and Hispaniolan faunas are even more similar.

Of all Cuban Sphecidae sl.; Prionyx thomae , Sphex dorsalis , Tachytes chrysopyga and Stictia signata have the largest parts of their ranges outside of Cuba.

Distribution within the Cuban Archipelago

Any analysis of the distribution patterns of the apoid wasps will be incomplete without keeping in mind the historical background. Their distribution is still not fully documented and the current ecosystems of Cuba are not the same as those of the past. Nevertheless, some protected natural areas exist in Cuba and some are little­altered and their wasp fauna may not have been badly impacted by human activities. The information contained in historical collections is also of help.

The keys (offshore islands) of the Cuban Archipelago have not been well surveyed (except for the Sabana­Camagüey Archipelago) and the poorly sampled mountainous areas almost certainly contain unknown species. Additional field work will increase the sample size of species known from few specimens. The study of the fauna of the keys that surround Cuba is of interest because these sites may be faunal exchange areas from which species disperse to (or from) the main island.

The restricted distribution of some species like Cerceris trinitaria , Cerceris hatuey or Oxybelus confusus (each recorded from one or two localities only, Fig. 3 ) probably reflects limited sampling effort or infrequent use of innovative collecting methods such as yellow pan traps, Malaise traps and flight interception traps. Their actual distribution may be much larger, not limited by ecological conditions that restrict endemic species, as is the case with many terrestrial gastropod molluscs in Cuba ( Espinosa and Ortea 1999). It is necessary to keep in mind that fragmentation and loss of habitats due to human activities have impacted the distribution of many species and Cuba is not an exception in this.

The power of dispersal of wasps should be high, since they fly and readily colonize new areas ( Evans 1975). However, some species have limited distributions because they are adapted to specific habitat conditions (nesting place, sources of nectar, availability of prey, or particular needs for temperature and humidity) ( Evans 1966, Bohart and Menke 1976). Almost half the Cuban species (44.2 %) are endemic to the Cuban Archipelago. One example is Ammophila cybele , which is restricted to xeric areas in the south of the eastern provinces of Santiago de Cuba and Guantánamo. This wasp (with a body length of around 20 mm) and with a distinctive provisioning behavior (it provisions its nests with butterfly larvae and nests in bare ground as do other species of the genus) might yet be found in other places. Sphex cristi , a rare, big black wasp (around 30 mm in length), with orange wings, was recently discovered at Caguanes, Sancti Spiritus, Cuba ( Fig. 3 ). This species is known only from females, which were observed nesting at the edge of big caves in this area ( Genaro and Juarrero 2000).

The limited distributions of some species, such as Oxybelus confusus and Cerceris hatuey from around Santiago de Cuba ( Fig. 3 ), could be an artifact of limited collecting effort. It is known that Pastor Alayo, an able entomologist and great collector, spent a lot of time exploring the Santiago de Cuba area, increasing the proportion of rare or new species there.

Among the species known from very few localities ( Fig. 3 ) and for which more sampling should increase their geographic range in Cuba the following can be mentioned Cerceris trinitaria (from the mouth of the Yaguanabo river, Trinidad and Moa, Holguín), Rhopalum soroanum (from Soroa, Pinar del Río), R. montanus (from Gran Piedra, Santiago de Cuba), Ectemnius ferrasi (from Moa, Holguín) and Psen venetus (from Gran Piedra and Pico Turquino).

The main Cuban mountainous regions of the East (Nipe­Sagua­Baracoa mountains and Sierra Maestra Mountain Range), Center (Guamuaya mountains) and West (Guaniguanico Mountain Range) contain the highest biodiversity and endemism of apoid wasps ( Fig. 3 ). Some species of Rhopalum , Cerceris , Psen , Pseneo , Hoplisoides and Trypoxylon (four undescribed species) are known only from these areas. These mountains have well preserved habitats and suitable conditions for nesting in the ground or inside cavities, and with suitable availability of prey.

Figures

FIGURE 2. Probable dispersal routes for Sphecidae and Crabronidae into the West Indies through alternative scenarios. Stippled arrows show major dispersal corridors for the occupation of the Proto­Antilles, at about 35–33 mya. Percentages are for Cuban species shared with other areas.

FIGURE 3. Map of Cuban areas of highest endemism and biodiversity, and only known localities for some species of apoid wasps.