ECOLOGY AND POPULATION BIOLOGY Does the Coffee Berry Borer (Coleoptera: Scolytidae) Have Mutualistic Fungi? JEANNETH PE ´ REZ, 1 FRANCISCO INFANTE, 1 AND FERNANDO E. VEGA 2 Ann. Entomol. Soc. Am. 98(4): 483Ð490 (2005) ABSTRACT Laboratory bioassays were performed to determine if a mutualistic association exists between three species of fungi and the coffee berry borer, Hypothenemus hampei (Ferrari). The fungi Fusarium solani (Martius), Penicillium citrinum Thom and Candida fermentati (Saito) were evaluated on the reproduction and survivorship of H. hampei. The fungi were evaluated at three concentrations: 5  10 2 ;5  10 4 and 5  10 6 spores/ml using coffee berries and meridic diets as substrate. The fungi did not affect the normal development of the insect and did not increase mortality at any concentration evaluated. When H. hampei was reared in berries, no signiÞcant differences in the total progeny production were detected between treatments involving fungi and the control. When reared on meridic diets, there was no clear trend to suggest a beneÞcial effect of a given species of fungus on H. hampei; at 40 d postinoculation, the total progeny production of the insect was higher than the control with C. fermentati; at 60 d it was higher with F. solani, and at 80 d there were no differences between treatments involving fungi and the control. Our results indicate that there were no clear positive effects of any fungi on the coffee berry borer either in berries or diets. Therefore, we conclude that H. hampei is not allied with fungi in mutualist relationships as was previously believed. KEY WORDS Hypothenemus, coffee berry borer, mutualism, fungi THE MAJORITY OF THE 6,000 described species of Sco- lytidae (Coleoptera) are involved in mutualistic rela- tionships with microorganisms, particularly fungi (Wood 1982, Booth et al. 1990). Because mutualism is deÞned as “an interaction between two species that is beneÞcial to both” (Boucher et al. 1982, Ricklefs and Miller 2000), the fungi beneÞt by being transported to new hosts by the insect; in turn, the scolytids cultivate and use the fungi as a food source (Whitney 1982). The associated fungi seem to be carried in specialized cuticular structures termed mycangia, which are found on different parts of the insect (Batra 1963). The coffee berry borer, Hypothenemus hampei (Fer- rari), is a scolytid of the tribe Cryphalini (Wood 1982) in which reports of fungal associations or mycetopha- gous habits (feeding on fungi) are unusual (Beaver 1986). Nevertheless, a possible mutualistic relation- ship between H. hampei and fungi has been suspected for many years (Le Pelley 1968, Villacorta 1989, Vil- lacorta and Barrera 1993). Such a hypothesis seems reasonable given that H. hampei is monophagous and insects feeding on a narrow food range often harbor populations of mutualistic microorganisms that sup- plement the restricted diet with critical nutrients (Ben-Beard et al. 2002). More than 50 species of fungi have been recorded from H. hampei and its galleries (Posada et al. 1993, 1998; Pe ´ rez et al. 1996, 2003; Rojas et al. 1999; Vega et al. 1999; Morales-Ramos et al. 2000; Dõ ´az et al. 2003; Peterson et al. 2003; Carrio ´ n and Bonet 2004). Of these, Fusarium solani (Martius) has been repeatedly isolated from H. hampei (Pe ´ rez et al. 1996, 2003; Vega et al. 1999; Rojas et al. 1999; Dõ ´az et al. 2003; Carrio ´ n and Bonet 2004), although the role that it plays in the biology of the insect is in dispute. Rojas et al. (1999) and Morales-Ramos et al. (2000) suggested a mutual- istic relationship between H. hampei and F. solani, whereas Pe ´ rez et al. (1996) and Dõ ´az et al. (2003) reported F. solani and Fusarium sp., respectively, as H. hampei pathogens. Understanding the nature of the relationship between the coffee berry borer and as- sociated microorganisms could provide important new clues applicable to management strategies for this pest. In an attempt to clarify this situation, we performed a series of laboratory experiments. We hypothesized that if H. hampei lives in association with a mutualistic fungus, the insect should suffer a decrease in progeny production in the absence of the fungus and that the absence of this organism should be generally detri- mental for the insectÕs development. The aim of the current study was to elucidate, by means of bioassays, whether Fusarium solani (Martius), Penicillium citri- num Thom, or Candida fermentati (Saito) are bene- Þcial to the development and reproduction of H. ham- pei. These fungi were selected because they were 1 El Colegio de la Frontera Sur, Carretera Antiguo Aeropuerto km 2.5, Tapachula, 30700 Chiapas, Mexico. 2 Insect Biocontrol Laboratory. Bldg. 011A, USDAÐARS, Beltsville, MD 20705Ð2350. 0013-8746/05/0483Ð0490$04.00/0  2005 Entomological Society of America Downloaded from https://academic.oup.com/aesa/article/98/4/483/22056 by guest on 09 May 2023