The Carpenter Bee Xylocopa Pubescens As an Agricultural Pollinator in Greenhouses Adi Sadeh, Avi Shmida, Tamar Keasar

The Carpenter Bee Xylocopa pubescens as an Agricultural Pollinator in Greenhouses Adi Sadeh, Avi Shmida, Tamar Keasar To cite this version: Adi Sadeh, Avi Shmida, Tamar Keasar. The Carpenter Bee Xylocopa pubescens as an Agricultural Pollinator in Greenhouses. Apidologie, Springer Verlag, 2007, 38 (6), pp.508-517. hal-00892288 HAL Id: hal-00892288 https://hal.archives-ouvertes.fr/hal-00892288 Submitted on 1 Jan 2007 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Apidologie 38 (2007) 508–517 Available online at: c INRA, EDP Sciences, 2007 www.apidologie.org DOI: 10.1051/apido:2007036 Original article The Carpenter Bee Xylocopa pubescens as an Agricultural Pollinator in Greenhouses* Adi Sadeh,AviShmida, Tamar Keasar Department of Evolution, Systematic and Ecology, the Hebrew University, Jerusalem 91904, Israel Received 24 December 2006 – Revised 6 May 2007 – Accepted 22 May 2007 Abstract – Many greenhouse crops depend on bees for pollination. Global declines of honeybee populations, and their limited efficiency in pollinating some greenhouse food-plants, motivate the search for additional pollinators. We evaluated the carpenter bee X. pubescens, a local species to Israel, as a pollinator of greenhouse-grown honeydew melons, in comparison to honeybees. We recorded the bees’ daily and sea- sonal activity patterns in relation to floral nectar levels, frequencies and durations of flower visits, and fruit quantity and quality. The bees’ daily foraging schedule on melon did not correlate with nectar yield and nectar production patterns by the flowers. Visit durations per flower were shorter for X. pubescens than for honeybees. Pollination by both bees resulted in similar fruit mass and seed numbers, but X. pubescens pollination increased fruit set threefold as compared to honeybee pollination. We conclude that X. pubescens can effectively pollinate melons in enclosures. carpenter bee / greenhouse / honeybee / honeydew melon / pollination 1. INTRODUCTION Pollination is thus one of the most im- portant ecosystem services provided to agriculture. This critical ecosystem service has Agricultural pollination is the first indis- been degrading in recent years, as honeybee pensable step in a process that results in colonies are declining in abundance because of the production of fruit, vegetables, nuts and habitat loss, diseases, pesticides, and other im- seeds. Agriculture is highly dependent on in- pacts (Kremen et al., 2002). An expert review sect pollination, in particular by the honeybee, panel recently confirmed that the last years of Apis mellifera L. (Cunningham et al., 2002). losses of honeybee colonies in North Amer- The economic value of insect pollination to ica leave us with fewer managed pollinators agriculture can be estimated on the basis of than at any time in the past 50 years, and that the abundance and market value of insect- the management and protection of wild polli- pollinated crops. In the United States, for ex- nators is an issue of paramount importance to ample, the value of crop pollination by insects the food supply system (Allen-Wardell et al., is estimated at US$14.6 billion (Morse and 1998). Calderone, 2000). $3 billion’s worth of this Native bee communities also provide pollination service is provided by native polli- pollination services, but the extent of these nator species (Losey and Vaughan, 2006), and services, and how they vary with land man- the remaining agricultural output is due to pol- agement practices, are largely unknown. In lination by honeybees. a pioneering study, Kremen et al. (2002) documented the individual species and ag- Corresponding author: T. Keasar, gregate community contributions of native [email protected] bees to crop pollination, on farms that var- * Manuscript editor: Jacqueline Pierre ied both in their proximity to natural habitat Article published by EDP Sciences and available at http://www.apidologie.org or http://dx.doi.org/10.1051/apido:2007036 Carpenter bees for greenhouse pollination 509 and in management type (organic versus con- ley (Gerling et al., 1989; Hogendoorn and ventional). Native bee communities provided Leys, 1993; Leys et al., 2000, 2002). Fe- full pollination services on organic farms near males of this species typically dig branched natural habitat even for a crop with heavy nests in dead wood (Ben Mordechai et al., pollination requirements (e.g., watermelon, 1978). They hibernate in the nests from the Citrullus lanatus). All other farms, however, end of October until the middle of March. Dur- experienced greatly reduced diversity and ing the activity season (March–October), fe- abundance of native bees, resulting in insuf- males are engaged in preparing brood cells, ficient pollination services. While this study while males form non-resource mating terri- demonstrates the importance of native bees to tories (Gerling et al., 1983). X. pubescens is crop pollination, only three species of native multivoltine, and may produce 4–5 genera- solitary bees (Nomia melanderi, Megachile ro- tions per year. Females are extremely long- tunda and Osmia cornifrons) are produced on lived and may be reproductively active for up a commercial scale to provide pollination ser- to 120 days (Gerling et al., 1981). Ovipositing vices. These pollinators are mainly used for females provision each brood cell with nectar alfalfa and orchard crops (Velthuis and van and pollen, lay a single egg in the cell, seal it Doorn, 2006). and proceed to construct the next cell. The de- In recent decades, insect pollinators have velopment from egg to adult takes 27–35 days. been actively introduced into greenhouses and Young adults that remain in the maternal nest nethouses. This effort was initiated in the before dispersal are provisioned with pollen by Netherlands, where honeybees were first in- their mother (Velthuis and Gerling, 1983; Van troduced into tomato greenhouses to replace der Blom and Velthuis, 1988), and obtain nec- hand pollination (de Ruijter, 1999). Honey- tar by trophallaxis (Gerling et al., 1983). bees were also shown to efficiently pollinate In natural habitats, X. pubescens foragers sweet peppers in enclosures (de Ruijter et al., feed on a wide variety of flower species, and ◦ 1991). Additional experiments demonstrated remain active at temperatures up to 40 C the superiority of bumblebees over honeybees (Gerling et al., 1989). This heat resilience in pollinating greenhouse tomatoes and egg- makes X. pubescens an attractive candidate plants (Pessarakli and Dris, 2004; Velthuis and pollinator for greenhouses in hot climates, van Doorn, 2006). Honeybees remain the main where temperatures often exceed the thermal greenhouse pollinator for crops that do not re- window of honeybees and bumblebees (Corbet quire mechanical buzzing of the anthers. In- et al., 1993). Initial favorable results, regard- sect pollination in greenhouses is now prac- ing the success of native Australian Xylocopa ticed worldwide, but is generally limited to in pollinating greenhouse tomatoes, provide an honeybees and bumblebees. The domestica- additional incentive for a quantitative evaluation and use of additional pollinator species in tion of their performance (Hogendoorn et al., enclosures is desirable as a countermeasure to 2000). the decreases in honeybee populations. In the present research, we tested the feasibility of adding the carpenter bee Xylocopa pubescens 2. MATERIALS AND METHODS (L.) to the arsenal of agricultural greenhouse pollinators. We compared X. pubescens’ polli- 2.1. General methods nation efficiency with that of the honeybee, the standard pollinating insect. Observations were conducted in a small (8 × The genus Xylocopa consists of about 469 4 × 4 m) greenhouse between April and October, species (Michener, 2002), predominantly dis- 2005. Temperature in the greenhouse ranged 11– tributed in tropical and subtropical climates, 38 ◦C during the study period, relative humidity and occasionally in temperate areas (Hurd and ranged 5–86%, and radiation levels were between Moure, 1963). X. pubescens, a local species 3 and 353 lux. The greenhouse was not illuminated, to Israel, is of Ethiopian origin, and has and provided no humidity control. We grew hon- reached Israel via the Syrian-African rift val- eydew melons in the greenhouse, and introduced X. 510 A. Sadeh et al. pubescens and honeybees in alteration into it (11 in- observation session, depending on the availability troductions of X. pubescens, 7 introductions of hon- of active, single-female nests. eybees). Preliminary observations indicated that X. pubescens foragers seem to behave normally within a few hours of introduction into the greenhouse. The 2.2.2. Apis mellifera condition of honeybee colonies, on the other hand, started deteriorating after a few days in the enclo- Honeybees are the standard pollinators of green- sure. These factors favoured short observation ses- house melons in Israel, and were therefore used as sions within the greenhouse. We therefore started a reference for the evaluation of pollination per- observing the bees on the

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