Saprophytic fungus collection by africanized bees in Brazil

Coleta de fungos saprofíticos por abelhas africanizadas no Brasil

SCIENTIFIC NOTE

Saprophytic fungus collection by africanized bees in Brazil

Coleta de fungos saprofíticos por abelhas africanizadas no Brasil

Anna F H Modro^I; Izabel C Silva^II; Dejair Message^II; Cynthia F P Luz^III

^IEscola Superior de Agricultura "Luiz de Queiroz", Depto. de Entomologia, Fitopatologia e Zoologia Agrícola, 13418-900, Piracicaba, SP; [e-mail]

^IIDepto. de Biologia, Apiário Central, Univ. Federal de Viçosa, 36570-000, Viçosa, MG; [e-mail], [e-mail]

^IIISecretaria do Meio Ambiente de São Paulo, Instituto de Botânica, Seção de Dicotiledôneas, Av. Miguel Estéfano, 3687, 04301-902, Água Funda, São Paulo, SP; [e-mail]

ABSTRACT

Cladosporium sp. collection by bees (Apis mellifera L.) was observed in Brazil at an apiary located in Minas Gerais, during November10-23, 2005, characterized by high air relative humidity and low availability of food resources (pollen and nectar).The nutritional composition of the fungi pellets presented high protein value, ethereal extract and organic matter.

Key words:Apis mellifera, Cladosporium sp., pollen, nutritional composition

RESUMO

A coleta de Cladosporium sp. por abelhas (Apis mellifera L.) foi observada no Brasil em um apiário localizado em Minas Gerais, no período de 10 a 23/11/05, caracterizado pela alta umidade relativa do ar e escassez de recurso alimentar (pólen e néctar). A composição nutricional das bolotas de fungos apresentou alto valor protéico, extrato etéreo e matéria orgânica.

Palavras-chave:Apis mellifera, Cladosporium sp., pólen, composição nutricional

Fungus development on bee pollen is widely known (Medina et al 2004, González et al 2005), as well as the occasional worldwide collection of fungus spores by bees of the genus Apis (Wingfield et al 1989, Shaw 1990). However, Cladosporium, a fungus dispersed in the air, found in rotten organic matter and as food contaminant, had not been reported in Brazil as being collected by Apis mellifera (L).

This work aimed to record for the first time collection of Cladosporium sp. by A. mellifera in Brazil, and to analyze its nutritional composition.

The experiment was developed in the municipality of Paula Cândido (20º49'S and 42º54'W) in Minas Gerais State, Brazil, in an area characterized by the presence of abandoned pasture, eucalyptus and coffee plantations, and fragments of semidecidual seasonal forest (Mata Atlantica), with 60 years of secondary succession. According to the Köppen system, the climate in the region is of the Cwb type, tropical in altitude, with rainy summers (Sept-Nov) and cold and dry winters (Apr-Sept), annual mean temperature ranging from 14ºC to 23°C and annual mean rainfall of 1,403.8 mm (Valverde 1958).

Aiming to collect pollen pellets, five africanized A.mellifera beehives were randomly selected and installed in Langstroth beehives with a pollen collector of the intermediary type coupled to the upper portion of each hive.

Collections of pollen pellets and flowered plants in the studied region were carried out from August 15 to November 23, 2005. The pollen pellet samples were cleaned, weighed, placed in plastic bags separated by sample and temporarily stored at -20ºC. The fungus pellets were separated from the pollen pellets based mainly on their characteristic dark turning into black coloration (Fig 1) and by light microscopy observations.

The fungus and pollen samples were sent to the Laboratory of Animal Nutrition (UFV – Department of Animal Science) for routine physico-chemical analyses, according to Silva (2002), for the determination of percentage of dry matter, organic matter, ashes or mineral matter, crude protein, ethereal extract and total carbohydrates. The fungi were identified at the Mycology Laboratory (UFV – Department of Phytopathology).

The Cladosporium sp. samples were collected, grouped as pellets and transported to the beehives by the bees in a manner similar to the pollen collection (Figs 2-4).

Although the pollen collectors had been installed in the field since August 15, 2005, the occurrence of fungus pellets in the samples was detected only during November 10-23, 2005, a period characterized by high air relative humidity (November average = 85%), energy feed scarcity (nectar) and protein feed (pollen), and consequently, by weakened beehives in the region studied.

The reasons bees collect fungi are unknown; however, low offer of protein resources near the apiary may have influenced bees, which collected other resources, such as fungi, to supply the needs of their colony, once sufficient pollen was unavailable (Shaw 1990).

In its nutritional composition, the Cladosporium sp. pellets presented higher ethereal extract, crude protein and organic matter and lower mineral matter and total carbohydrate values than the average of the results for these nutritional components from the pollen gathered during the same period (Table 1), with the pollen types most collected during the fungus collection period being Alchornea and Cecropia. Despite the high protein value of the fungi evaluated, the bee capacity to distinguish the nutritional composition of the feed to be collected is quite discussed (Pernal & Currie 2001, Cook et al 2003). However, Wingfield et al (1989) observed that A. mellifera apparently prefers collecting the fungus Melampsora ricini over pollen, whenever the fungus is available.

The fungi collected could be used as a protein resource for the brood; however, since this is predominantly a saprophyte genus, some species may induce the occurrence of diseases in the beehives, and depending on the proportion of spores collected in comparison to the pollen stocked, they may negatively affect beehive balance (Prest et al 1974, Shaw 1990, Calderon et al 2004).

The plants observed under flowering during the aforementioned period were Baccharis dracunculifolia, B. melastomaefolia, Enterolobium contortisiliquum, Hydrangea macrophylla, Lantana sp., Leonurus sibiricus, Murraya paniculata, Petrea sp., Petroselinum crispum, Rosa sp., Stachytarpheta sp., Tibouchina granulosa, Verbena bonariensis, Vismia martiana and Vitex sellowiama, most being arbustive or herbaceous (83.3%) located on dirty pastures or gardens (83.3%).

According to Stevenson (1974), Cladosporium is generally associated with aphids, since the honeydew secreted by these insects is an important attraction for fungus development. Thus, both the flowering plant species and the honeydew secreted by aphids may have influenced the bee attraction for the fungus sources. Another factor that may have influenced the occurrence and collection of Cladosporium over this period was the presence of coffee plantations near the apiary during fruit ripening, because of the commonness of the coffee berry contamination by fungi (Chalfoun et al 2007).

In conclusion, despite the reasons A. mellifera collected saprophytic fungi collection (Cladosporium sp.) in the study area remain unknown, the interactions among the climatic factors (high humidity), food scarcity (pollen and nectar), high protein value of the fungi, and existence of honeydew and coffee berry contamination in the field may have all affected bee behavior in collecting fungus.

Acknowledgments

We thank UFV Professors Robert Weingart Barreto, Ph.D., for Cladosporium sp. identification and Edenio Detmann, D.S., for the nutritional analysis of the samples.

Received 24/IX/07. Accepted 09/X/08.

Edited by Fernando Noll – UNESP

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Publication Dates

• Publication in this collection
  13 July 2009
• Date of issue
  June 2009

History

• Accepted
  09 Oct 2008
• Received
  24 Sept 2007