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The present paper aims to find an explanation for the presence of exceptionally long and branched nests in the Xylocopini species. Two giant nests of Xylocopa violacea (L., 1758), excavated in a Prunus persica trunk, were found in 1994: M94/1 and M94/2. The former was formed by seven tunnels, four of which were ascending and 111 mm in average length, and 3 were descending and 108 mm in average length; the total length of the nest was 795 mm. M94/2 showed 9 tunnels, 7 of them were ascending and 98 mm in average length, and 2 were descending and 66 mm in average length; the total length of the nest was 856 mm. Nests of similar or slightly larger sizes have been reported for X. frontalis (social and multivoltine), X. hirsutissima (social and multivoltine), X. subvirescens and Lestis bombylans (communal nesting and multivoltine). Giant nests are common in both social and multivoltine species, since the founder female is helped by the daughters of the 1st generation in the construction of the cells of the 2nd generation, nest lengthening, and even oviposition. Moreover, the nest can be reused for several years and therefore subjected to further lengthening. The explanation for these two giant nests is not simple for the following reasons: 1) X. violacea is considered by all the authors as univoltine and solitary without any mother-daughters interaction; 2) the M94 nests were excavated in 1994, and therefore cannot be the result of lengthening due to its reuse; 3) the M94 nests had an entrance each, and therefore cannot be the fortuitous, or otherwise, result of the mergence of two or more nests. Therefore, five hypotheses are here formulated, based on my 10-year observations and literature data on this and other co-generic species. The main conclusion is that it is necessary to reconsider the whole life cycle of X. violacea, by carrying out further investigations on the life of the founder female after the nest has been completed, as well as on the fecundity of the Xylocopini species from the evolutionary standpoint.
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... La tribù Xylocopini (Apidae) include tre generi: Xylocopa Latreille, 1802 (cosmopolita), distribuito in Italia con tre specie; Lestis Lepeletier & Serville, 1828 (Australia); Proxylocopa Hedicke, 1930 (Medio-Paleartico) (Vicidomini, 1997b(Vicidomini, , 1997c(Vicidomini, , 2001). Le specie della tribù Xylocopini sono caratterizzate da una notevole uniformità nei comportamenti di nidificazione e nelle caratteristiche morfostrutturali dei nidi, se si fa eccezione per il genere Proxylocopa, con habitus del nido ipogeo (e.g.: Vicidomini, 1996aVicidomini, , 1997a). Tutte, infatti, nidificano scavando tunnels nel legno morto con le mandibole, e per questo gli Xylocopini vengono indicati come "large carpenter bees" (Vicidomini, 1995). ...
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The description of a rare morphological aberration on Xylocopa violacea legs is the aim of this contribute. ➽See Hind Wings -- https://www.researchgate.net/publication/256485069_Biologia_di_Xylocopa_%28Xylocopa%29_violacea_%28L._1758%29_%28Hymenoptera_Apidae%29_una_rara_aberrazione_morfologica_delle_ali_posteriori ➽Complete Review on Xylocopini -- https://www.researchgate.net/publication/256485308_World_bibliography_on_Xylocopini_tribe_(Insecta_Hymenoptera_Apoidea_Apidae_Xylocopinae)_Xylocopa_Latreille_1802_Lestis_Lepeletier__Serville_1828_Proxylocopa_Hedicke_1938._II_edition
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Abstract - SALVATORE VICIDOMINI & CARLO MELONI - Xylocopini (Hymenoptera: Apidae: Xylocopinae) contained in the Italian entomological collections: sardinian collections. The list of Xylocopini tribe specimens (Apidae) contained in the Sardinian (Italy) collections is the aim of this contribute. There are 123 specimens distributed in 5 collections: 97 specimens in the Entomology institute of Agronomy Faculty of Sassari, 18 in the private collection of Carlo Meloni (Cagliari), 5 in the private collection of Francesco Rattu (Cagliari), 2 in the Zoology Institute of Cagliari University, 1 in the private collection of Sechi (Cagliari). The following three species have been recognized: Xylocopa violacea (L.), X. iris (Christ), X. combusta Smith; 42 new faunistic records are reported for Sardinia and one for Toscan Islands. Key words: Xylocopini, Xylocopa violacea (L.), X. iris (Christ), X. combusta Smith, Sardinian Entomological Collections. Riassunto - SALVATORE VICIDOMINI & CARLO MELONI - Xylocopini (Hymenoptera: Apidae: Xylocopinae) presenti nelle collezioni entomologiche italiane: le collezioni della Sardegna. Scopo di questo contributo è quello di elencare il materiale presente nelle collezioni entomologiche sarde appartenente alla tribù Xylocopini (Apidae). Ci sono 123 esemplari distribuiti in 5 collezioni: 97 nell’Istituto di Entomologia della Facoltà di Agraria di Sassari, 18 nella collezione privata Carlo Meloni (Cagliari), 5 nella collezione privata Francesco Rattu (Cagliari), 2 nell’Istituto di Zoologia dell’Università di Cagliari, 1 nella collezione privata Sechi (Cagliari). Sono state individuate le tre specie seguenti: Xylocopa violacea (L.), X. iris (Christ), X. combusta Smith. Sono state individuate 42 nuove segnalazioni per la Sardegna ed una 1 per l’arcipelago toscano. Parole chiave: Xylocopini, Xylocopa violacea (L.), X. iris (Christ), X. combusta Smith, Collezioni Entomologiche Sarde.
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The systematic revision of Xylocopini (Apidae) contained in the Roma Zoological Museum is the aim of this contribute. The revision has regarded the collections Lepri, Luigioni, Vita and the miscellaneous section. The following species have been recognized: X. combusta, X. frontalis, X. iris, X. valga, X. violacea, X (Koptortosoma) sp, X. (Shoenherria) sp. Cosenza (Calabria) and Siena (Toscana) are two new provincial faunistic records for X. valga.
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The Xylocopini (Apidae) collection of F. Silvestri Entomological Institute of Portici has been revised. The specimens in collection are 248 from 14 nations (Brasil, Belgian Congo, Etiopia, Erytrea, Grece, French Guinee, Italy, Lybia, Dominican Republic, Senegal, Somalia, Spain, W. Africa, not specified nation of South-East Asia) and belonging to the following species: Proxylocopa (Proxylocopa) olivieri (Lepeletier, 1841), Xylocopa (Copoxyla) iris (Christ, 1791), X. (Koptortosoma) aestuans (Linnè, 1758), X. (Koptortosoma) albiceps Fabricius, 1804, X. (Koptortosoma) caffra (Linnè, 1767), X. (Koptortosoma) caffra var. mossambica Gribodo, 1894, X. (Koptortosoma) citrina Friese, 1909, X. (Koptortosoma) imitator Smith, 1854, X. (Koptortosoma) modesta Smith, 1854, X. (Koptortosoma) olivacea (Fabricius, 1787), X. (Koptortosoma) senior Vachal, 1899, X. (Koptortosoma) sp., X. (Mesotrichia) combusta Smith, 1854, X. (Mesotrichia) flavorufa (DeGeer, 1778), X. (Mesotrichia) mixta Radoszkowski, 1881, X. (Neoxylocopa) mordax Lepeletier, 1841, X. (Neoxylocopa) grisescens Lepeletier, 1841, X. (Platynopoda) magnifica (Cockerell, 1929), X. (Xenoxylocopa) chiyakensis (Cockerell, 1908), X. (Xenoxylocopa) inconstans Smith, 1874, X. (Xylocopa) valga Gerstaecker, 1872, X. (Xylocopa) violacea (Linnè, 1758), X. (Xylomelissa) sp. The Italian regions represented in the collection are as follows: Basilicata, Calabria, Campania, Emilia Romagna, Lombardia, Marche, Molise, Puglia, Sardegna, Sicilia, Toscana, Veneto.
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See also these papers on sexual biology: ►https://www.researchgate.net/publication/258005579 ►https://www.researchgate.net/publication/258090036 ►https://www.researchgate.net/publication/257138095 ►https://www.researchgate.net/publication/232990708 ►https://www.researchgate.net/publication/257132358 ►https://www.researchgate.net/publication/257132362 ►https://www.researchgate.net/publication/257132355 ► https://www.researchgate.net/publication/256485308 ****** Copulation in Xylocopa violacea is described, followed by a review of copulatory ethology of Xylocopini species. A total of 659 male-female interactions in X. violacea were observed, of which 147 resulted in matings. The catching of females takes place in the air; they are located by sight and perhaps, at close quarters, also chemically. Copulation happens on a perch and lasts 19 s. During copulation the male stimulates the females tactically (antennae) and acoustically (wings). Matings mostly occur in March (83.3%) and between 11.01-13.00 h (70.1%), at an average temperature of 17.44-17.62 °C. Females often (68.7%) reject males. Comparison of the copulatory behaviour among Xylocopini species reveal the following shared characteristics: female and (rare) male precopulatory choice (on unknown bases); cryptic female choice; copulatory male courtship; sperm competition.
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The sex ratio of Xylocopa violacea L. was investigated and studied through the analysis of 37 nests, in different years. In total 93 male pupae and 136 female pupae (sex ratio: 0.68 = 1 male per 1.47 females) were obtained. Sex ratio was female biased in 23 nests (62.2%) and male biased in 8 nests (21.6%); in 3 nests sex ratio was 1:1 (8.1%), instead in 2 nests (5.4%) the offspring was totally female and in 1 was male only (2.7%). In 1994 sex ratio was 0.35 (1 male per 2.86 females in 8 nests); in 1995 sex ratio was 0.32 (1 male per 3.13 females in 6 nests); in 1996 sex ratio was 0.84 (1 male per 1.19 females in 10 nests). Data show that in X. violacea sex ratio was always female biased and this is in accordance with Xylocopini sex ratio. Within Xylocopinae, Ceratinini and Allodapini show the most female biased sex ratio. This life history trait is opposite to that known for Bombini and Anthophorini (sex ratio male biased).
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See also these papers: ►✉◀https://www.researchgate.net/publication/236334723_Biologia_di_Xylocopa_violacea_(L.)_(Hym._Apidae)_biologia_della_nidificazione ►✉◀https://www.researchgate.net/publication/236334738_Biologia_di_Xylocopa_(Xylocopa)_violacea_(Linn_1758)_(Hymenoptera_Apidae)_storia_naturale_del_nido_dopo_il_suo_completamento ►✉◀https://www.researchgate.net/publication/256457322_Biologia_di_Xylocopa_(Xylocopa)_violacea_(Linn_1758)_(Hymenoptera_Apidae)_storia_naturale_della_nidificazione ____________________________________ ABSTRACT. - The aim of this contribution was to determine the ralationships among sex ratio-maternal investment-sex allocation-offsping size-development/mortality (part I) and for experimental alteration of larval food (= PP) mass, immagine size, offsprings pre-immaginal survival and some specific taxonomical characters (part II) in a Xylocopa violacea (L.) population of Southern Italy (Campania) are the aims of this contribute. The main results are the following. 1) Observed sex ratio 0.684 (59.39% of females); expected sex ratio based on pollen paste weight 1.264, on imagine weight 1.339, on cell lenght 1.134; sexual cost ratio based on pollen paste weight 0.791, on imagine weight 0.747, on cell lenght 0.882. 2). With respect to males, females are larger, are allocated after position III in the paedotrophic cell (males in outer cells), have a longer total developmental time, consume pollen paste more rapidly, have a larger cells and have a havier PP. 3) Founding females provision outer cells with less pollen paste than inner cells for both sex; both males and females grow large in inner cells compared to outer ones. 4) X. violacea shows a high energetic conversion value (46%), without sexual differences. 5) Egg developmental time is higly variable, but pupal developmental time varies little. 6) Offsping size and sex ratio per nest are directly related to nest cell numbers (= nest size). 7) The by-cell variation pattern observed for observed-espected sex ratio, PP, cell lenght and in part egg+larva instar duration and total development duration, can be summarized in one pattern with the position III simmetric center position; the following position groups are recognizable: I-II; III; IV-V; VI-VIII; IX-XIV. 8) Pre-imaginal death rate is different in two sex. 9) Results do not confirm the Fisherian theory of sex ratio nor Local Resource Enhancement theory. 10) Larvae can survive until the immaginal instar with about 50% of normal PP mass, creating live dwarves. 11) The prepupa larvae with mass < 0.4 g shows a very high pre-immaginal mortality rate. 12) Larva experimentally provisioned with low PP, exhibits the feeding behaviour for many hour after PP is completely consumed. 13) The production of giant individuals is less efficient than dwarf ones. 14) Larvae experimentally provisioned with ad libitum PP did not consume the entire food reserve. 15) Larval feeding behaviour is unmodified by PP presence/absence, but is controlled by a biological clock. 16) In several cases an instantaneous mechanical reproductive barrier has been obtained because of great difference between giant and dwarf individuals. 17) Dwarf individuals have a modified clypeal shape compared with average size individuals. The following two work-hypotheses are proposed. A) Xylocopini species larger than X. violacea have an "extended" biological clock that increases PP consumption in larvae, resulting in larger individuals; it is possible that during speciation events in Xylocopini in which there is size variation mother and daughter species, the regulation of larval biological clock happens during the speciation event. B) In species with a wide distribution such as X. violacea, dwarf offsprings could be favourable in xerophilic environments results in two possible effects: B1) speciation, if two populations become reproductively isolated; B2) intraspecific increase of variation for size, without reproductive isolation, could be incorrectly interpretated as interspecific variation. Published data on these two effects are discussed.
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Detailed etological study of pollen paste (PP) preparation and biochemical analyses in Xylocopa violacea, are the aims of this contribute. Pollen and nectar are collected on Papaver rhoeas, P. hybridum, Actinidia sinensis, Calystegia sepium, Althaea rosea, Antirrhinum majus, Convolvulus arvensis, Jasmineae officinalis, Spartium junceum. From Phaseolus vulgaris and Poinciana gillesii only nectar is collected. Hindlegs (tibiae+femora) are the fondamental body part in pollen transport. In PP preparation, nectar dehydrated and pollen are mixed. During PP preparation, pollen undergo a first processing without allocation (not mature PP) and then to second double processing with double allocation (mature PP). During PP processing-maturation, antennae are frenetically mouved, to assay the state of PP maturation. The free amino acids total quantity is 1.36% of PP; more than 50% of them is PRO. Glucose+fructose is 43.5% of PP. Proteins are about 15%. Lipids are a negligible quantity. A complete provision of PP has an average mass of 1276 mg with an energetic content of 21 Kj/(g dry mass). Review and comparative analyses of the biochemical data on Xylocopini specie PP is presented and also compared with data on Apis honey.
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Fifty-nine nests of Xylocopa violacea in dried canes and 11 in poles were analysed. Two branched nests in a dry and rotten trunk were also examined. Poles and canes were artificial substrata, as they were used as supports for fruit and vegetable farming. The poles were derived from Castanea sativa and, to a lesser extent, from Ficus carica, the canes from Arundo donax. Eight parameters related to the morphology and position of the canes, and 13 related to nests completed and abandoned in poles were considered. Furthermore, the digging behavior was followed up in 10 nests. In poles and branches, nest entrance was mainly in the N-S direction; the most frequent diameter was 11 mm; 52/61 (85.2%) entrances found were situated at a height exceeding 41% of the total length of the poles or branches. The canes used by females for nesting were at a minimum distance of 860 mm from the ground; the entrance was 9-14.5 mm in diameter. Nests in canes generally occupied the first internode. Damaged canes and poles or those at ground level were systematically avoided for nesting. These peculiarities can be considered as antipredatory measures against Cremastogaster scutellaris, Podarcis sicula and other females of X. violacea.
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►✉◀ See also these papers: ➽X. violacea Sociality & Evolution - https://www.researchgate.net/publication/236334738 ➽X.violacea Sexual Biology - https://www.researchgate.net/publication/258088835 ➽X.violacea Nesting Biology - https://www.researchgate.net/publication/232990708 ➽X.violacea Foraging Biology - https://www.researchgate.net/publication/256546876 ➽X.violacea Dimorphism - https://www.researchgate.net/publication/257138153 ➽Xylocopini Systematics & Collections - https://www.researchgate.net/publication/256461358 ➽Xylocopini Italian distribution -- https://www.researchgate.net/publication/256461362 ➽➽ABSTRACT.-- Nest-building behaviour was studied in Xylocopa violacea, with particular attention to that exhibited in the construction of each cell, from the formation of the pollen paste to the construction of the diaphragm. Seven inside characteristics of 28 nests excavated in dried Arundo donax canes were determined. The cell length ranged from 14 to 20 mm. The diaphragms separating the cells were 2 mm thick in the middle, and 4-5 mm at the edge. In 37 additional nests, only data on some characteristics were taken: (a) colour of the pollen paste; (b) cane internode used for nesting. X. violacea is univoltine and solitary, and as in all the other Xylocopa species, female average fecundity is very low (7.43 eggs per nest), despite considerable maternal investment. Univoltine Xylocopa species are less fertile than multivoltine Xylocopa species because of the one to three supplementary generations per year.
Phenologie des grands apoldes (fiymenoptera, Apoideaz Bnmbus, Xylacopa, Habropocla) dans le Massif des Maures (France, Var) — In: Lhonore ] Eds — Inventaire et carto» graphie des invertebres eomine contribution a 121 gestion (les milieux naturels francais - Actes Sem, Mans 6—7/Nov
  • P Maurin
  • H Guilbot
  • R Keith
DUHAYON (3., RASMONT P., 1995 — Phenologie des grands apoldes (fiymenoptera, Apoideaz Bnmbus, Xylacopa, Habropocla) dans le Massif des Maures (France, Var) — In: Lhonore ]., Maurin H., Guilbot R., Keith R, Eds — Inventaire et carto» graphie des invertebres eomine contribution a 121 gestion (les milieux naturels francais - Actes Sem, Mans 6—7/Nov./1992; (Mus. Nat. Hist. Nat. Paris) Collec. Patr. Natur. Ser. Patr. Ecol, 13: 165168