The tribe Ericrocidini includes 11 genera and 44 species, known only from the New World. All species of this tribe are cleptoparasites, most of them on Centris spp. (Rocha-Filho et al. 2009; Martins et al. 2017; Michener 2007), although Mesoplia Lepeletier also occurs in nests of Epicharis Klug (Rocha-Filho et al. 2008). Host associations are still poorly documented, sometimes only known from indirect observations (Michener 2007). Two species have been recorded in C. analis nests: Aglaomelissa duckei Snelling & Brooks, 1985 and Mesocheira bicolor Lepeletier & Serville, 1825.

Aglaomelissa Snelling and Brooks is a monotypic genus known from Costa Rica and northern South America (Michener 2007, Moure and Melo 2012). Rocha-Filho et al. (2009) reported that A. duckei emerged from nests of two species of Centris (Heterocentris) in the Brazilian Amazon: Centris analis and C. terminata. Considering the abundance and distribution of C. analis, A. duckei may be an important parasite in the Amazon region. However, because of the scarcity of information on A. duckei hosts, it is not possible to indicate how often this parasitic species attacks C. analis, or whether it is specific to Centris (Heterocentris).

Mesocheira Lepeletier and Serville is also a monotypic genus that occurs throughout the Neotropics, from Mexico to Paraguay. Mesocheira bicolor is frequently reported in trap nest studies but little is known about its cleptoparasitic behavior, biology and specificity. This species was recorded parasitizing both Centris (Hemisiella) and Centris (Heterocentris) species, as follows: C. dichrootricha Moure, 1945, C. nitida Smith, 1874, C. tarsata Smith, 1874, C. trigonoides Lepeletier, 1841 and C. analis Fabricius, 1804 (Parker 1977; Morato et al. 1999; Jesus and Garófalo 2000; Aguiar and Martins 2002; Gazola and Garófalo 2002; Aguiar and Garófalo 2004; Aguiar et al. 2005). Centris analis is the only species of this list in subgenus Centris (Heterocentris), and the parasitism rates were low considering the wide distribution and the relative frequency of M. bicolor in trap-nesting bee studies. In observations performed in trap-nests set in the municipality of Paudalho, Mesocheira bicolor females only attacked nests of C. tarsata, even though the abundance of C. analis nests was much higher in the studied area. Similar patterns were reported by Araújo et al. (2018) and Oliveira-Rebouças et al. (2018). The apparent preference of M. bicolor for C. (Hemisiella) nests may be due to the type of material used by female hosts to construct and/or provision the brood cells. The species of this subgenus are known to use a mixture of sand and oils (Vinson et al. 1996; Morato et al. 1999; Pereira et al 1999) while C. (Heterocentris) females tend to use plant material and oils (Jesus and Garófalo 2000; Aguiar and Garófalo 2004; Oliveira and Schlindwein 2009). The low rates of parasitism could also be due to the differences in larval foods stored in brood cells. The cell provisions of C. analis consist of pollen and nectar without floral oils, which may be a characteristic of the subgenus (Jesus and Garófalo 2000; Aguiar and Garófalo 2004), while C. tarsata females use a mixture of pollen, nectar, and oil (Aguiar and Garófalo 2004). Based on the available information, it seems M. bicolor is not an effective parasite of C. analis, with only occasional occurrence in nests of this species.

The tribe Megachilini includes a large number of taxa with great morphological and behavioral diversity. Most of the cleptoparasitic species belong to the cosmopolitan genus Coelioxys, which includes over 200 species in South America (Moure et al. 2012, Michener 2007). Most Coelioxys spp. are cleptoparasites of Megachile, although there are records of parasitism of other genera of both Megachilinae and Apinae, including Centris (Rocha-Filho and Packer 2015; Michener 2007).

Coelioxys spp. have often been recorded as parasites of C. analis in samples with trap nests (Table 1). In most of these studies, one single species of Coelioxys was observed parasitizing C. analis nests, but in several of them the species is not identified due to the lack of taxonomic studies of the genus (Rocha-Filho 2015). The present work reports on vouchers identified to species level for the first time. All specimens examined belonged to Coelioxys nigrofimbriata (see references in Table 1). Only Aguiar and Martins (2002) and Gazola and Garófalo (2009) found more than one Coelioxys species attacking C. analis nests in the same area; two and three, respectively. The material from Gazola and Garófalo (2009) identified as Coelioxys aff. uhleri from Estação Ecológica de Paulo de Faria actually corresponds to C. nigrofimbriata. The other two species reported by Gazola and Garófalo (2009), the material of Aguiar and Martins (2002) and also the other surveys listed in Table 1 as Coelioxys spp. could not be examined to confirm the identification at this time.

Behavior of Coelioxys nigrofimbriata. This species was described from the state of Amazonas, Brazil, but the observation of specimens in trap-nest studies demonstrated that it is widely distributed in Brazil, occurring from Amazonas to Paraná. Coelioxys nigrofimbriata females usually hover in front of the trap nests to locate a nest that is being provisioned. Often, only one or two females of the cleptoparasite bee were seen at the same time in the wooden blocks. The parasite enters, inspects and deposits an egg when the host female is absent. When the amount of larval food is not sufficient, the parasite leaves the nest, lands near the nest entrance and waits for the host to deposit more pollen (up 70 min, according to Gazola and Garófalo 2002). This behavior of ovipositing into open cells, and waiting near the entrance agrees with the general patterns described for the genus (Scott et al. 2000, Michener 2007, Vinson et al. 2011). The females of C. nigrofimbriata were observed within 3 to 20 cm of the nest, with the head directed towards the nest entrance, similar to what was described for Coelioxys chichimeca Cresson, 1878 (Vinson et al. 2011). Females of C. analis that returned from foraging trips expelled parasites that were close to their nests. However, the parasites would return a few minutes later and repeat the behavior. The observations described here agree with the remarks made by Gazola and Garófalo (2002) (cited as Coelioxys sp.).

Centris analis was active throughout the year, with nest construction recorded in every month except June and July, while the C. nigrofimbriata attacks occurred between November and May. Centris analis built 116 nests during the study period, of which 28 were attacked by C. nigrofimbriata. Of the 116 nests, 97 were built during the hot and wet season, with the highest frequency occurring in March (n=46). These nests produced 274 individuals of the host species and 32 C. nigrofimbriata. The number of brood cells constructed by C. analis per nest ranged from one (n= 19) to nine cells (n= 1), with four (n=22) and five (n= 22) cells being the most abundant. Of the 28 nests attacked by cleptoparasite bees, 24 produced only one parasite, and four produced two parasites. The highest frequencies of attacks occurred in the months that C. analis had the highest nesting frequencies (January, March and April) (Figure 1). Coelioxys nigrofimbriata parasitized exclusively nests of C. analis even though there were also nests of C. tarsata in the same area. These data demonstrated that parasitism activities of C. nigrofimbriata were strongly synchronized and dependent on the construction of nests by C. analis.

Figure 1. 

Number of Centris analis nests built and number of nests attacked by Coelioxys nigrofimbriata from January to December 2017.

Bombyliidae is one of the largest families of true flies with over 5000 described species. Their representatives are most abundant and diverse in arid and semiarid regions of the world, with about 450 species in the Neotropical Region (Ávalos-Hernández et al. 2014; Yeates and Greathead 1997; Carvalho et al. 2012). Anthrax Scopoli is also a diverse taxon, with 248 species worldwide, whose immature stages are all ectoparasitoids of larvae and pupae of holometabolous insects living in tubular nests or cells (Marston 1970, Ávalos-Hernández et al. 2014). Yeates and Greathead (1997) listed 70 species as ectoparasitoids of larvae and pupae of bees and wasps, and over 300 host records, but available information about host preferences and specificity for the genus is still scarce (Marston 1970). Among the bees, six studies recorded three species of Anthrax in nests of C. analis (Table 1). In all these trap-nest studies, Anthrax species seemed to be generalist, emerging from nests of C. analis as well as other species of bees and wasps. No additional data was found on the parasitic behavior of Anthrax in nests of C. analis.

Conopidae is a widespread family of flies with about 780 species and 56 genera (Carvalho et al. 2012). The larvae of species for which biology is known are obligatory endoparasitoids of other insects. Representatives of three subfamilies (Conopinae, Myopinae and Dalmanniinae) are known as internal parasites of aculeate Hymenoptera, and some species may have a negative effect on populations of pollinators (Gibson et al. 2013; Melo et al. 2008). Females attack adult bees, inserting an egg on or within the bee’s abdomen while they are foraging, or in flight. The larva develops inside the abdomen of the host, feeding on internal tissue and hemolymph, and pupates in situ, killing the host (Santos et al. 2008).

Species of the genus Physocephala Schiner are solitary koinobiont endoparasitoids of several genera of bees such as Anthidium Fabricius, Anthophora Latreille, Apis Linnaeus, Bombus Latreille, Centris Fabricius, Epicharis Klug, Eulaema Lepeletier, Euglossa Latreille, Halictus Latreille, Megachile Latreille, and Xylocopa Latreille (Rasmussen and Cameron 2004; Melo et al. 2008; Santos et al. 2008; Couto and Camillo 2014). Santos et al. (2008) reported on conopid flies attacking C. analis and recorded nine species of Physocephala in southeastern Brazil (Table 1). Couto and Camillo (2014) also recorded eight Physocephala species emerging from dead specimens of C. analis. Couto and Camillo (2014) also observed that parasitized females present behavioral changes, and deposited extra oil on the nest occlusion or closed empty nests. These parasitic associations do not appear to be specific, but impact the behavior of the female bees. Behavior data for C. analis are still scarce, but these parasitic flies can have a high incidence of attacks and decrease bee populations as reported for Bombus spp. by Abdalla et al. (2014) and Malfi et al. (2014).

Phoridae is a cosmopolitan family of flies with over 4000 described species (Brown and Smith 2010). Many species are well known as parasitoids of corbiculate bees such as stingless bees, bumblebees and honey bees (Lucia et al. 2013; Ament et al. 2014). There are also records of species of Melaloncha Brues attacking Augochlorini (Halictidae) (Wcislo et al. 2004), Centridini (Apidae) and Euglossini (Apidae) species (Ament et al. 2014). The genus occurs only in the Neotropical Region and comprises the largest group of bee-killing parasitoids, with 167 described species. Female flies attack bees by injecting an egg into their body through the membrane between sclerites and the larvae develop as internal parasitoids, consuming and killing the hosts (Brown 2004; Brown and Smith 2010; Brown 2016). The record is exceptional and it is based on the observation of a puparium removed from the mesosoma of a Centris analis (Ament et al. 2014).

Meloidae is a family of beetles that includes almost 2500 species in approximately 120 genera. Meloid larvae are known as parasites of grasshoppers and larvae of Apoidea or other aculeate Hymenoptera (Bologna and Pinto 2001; Lückmann and Assmann 2006). The family has a distinctive form of metamorphosis, with the presence of a triungulin first instar in most taxa. This first instar, depending on the group, feeds on eggs of Acridoidea or provisions and larvae of Apoidea or other aculeate Hymenoptera. In the taxa that attack apoid hosts, the triungulin is phoretic, and is taken to the larval food indirectly by the adult bees that visit flowers (Bologna and Pinto; 2001). Some species have been documented as parasites of Melitoma Lepeletier and Serville (Roubik 1989), Epicharis Klug (Gaglianone 2005), Monoeca Lepeletier and Serville (Rozen et al. 2006) and Eufriesea Cockerell (Kamke et al. 2008). Tetraonyx Latreille (Morato et al. 1999) and Nemognatha Illiger (Gazola and Garófalo 2009) were recorded in C. analis nests trap-nest surveys, but without species-level identification, information about the biology or parasitic behavior.