Bees as pollinators in Brazil - USP

honey bees were introduced in the New World
in the middle 1960´s, and they reached Central
America in 1985, he compared the coffee
yields of the period before and after its introduction.
After the arrival of Africanized bee in
Central America, coffee yields in most countries
of this region increased substantially,
except for the Caribbean countries (e.g. Haiti),
where native and introduced pollinators were
absent. In the Old World, where honey bees
were always present, coffee production did
not varied in the same rate than the New
World. Countries that experienced an intensive
land usage and loss of habitats for pollinators
had reduced yields (loss of 20-50%),
although they had increased cultivated areas
(Ivory Coast, Ghana, Kenya, Cameroon,
Indonesia, El Salvador and Haiti) (Roubik,
2002). This work stressed the importance of
native and introduced pollinators for coffee
yields, although he did not analyze the pollination
behaviour itself.
Ricketts (2004), in experiments performed
at Costa Rica during 2001-2002,
showed that eleven eusocial bees (10 native
plus A. mellifera) were the most common visitors
of coffee (C. arabica) shrubs, and that
the distance of the forest fragments to the
cultivated areas significantly influenced coffee
visiting by these bees. Bee richness, overall
visitation rate, and pollen deposition rate
were all significantly higher in sites within
approximately 100m of forest fragments than
in sites far away (up to 1.6km). Apis mellifera
foragers accounted for more than 90% of all
visits in distant sites, and where Apis were not
present, native species as meliponine bees
accounted for most of the visits at near sites.
This is due to the smaller flight range of
meliponine bees which have a typical flight
range of 100-400m (van Niewestadt &
Iraheta, 1996, Heard, 1999), although maximum
observed flights ranged from 1 to 2 km
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(Roubik & Aluja, 1983). When Apis abundance
declined substantially, from 2001 to
2002, visitation rates dropped about 50% in
distant sites, but only 9% in near sites. This
can be explained by the compensating effect
of native bees, which replaced Apis as the
most important visitor in nearby sites. So,
according to the author, forest fragments
provided nearby coffee with a diversity of
bees that increased both the amount and stability
of pollination services by reducing
dependence on a single introduced pollinator
(Ricketts, 2004).
Similar results were found in Brazil (De
Marco & Coelho, 2004) and Indonesia (Klein,
et al., 2003b,c). Coffee (C. arabica) branches
with free access to pollinators produced more
fruits in farms where there were forest fragments
nearby. Coffee production increased
14.6% when the services of pollinators were
available (De Marco & Coelho, 2004). Similarly,
C. canephora and C.arabica fruit set increased
with the increase of diversity and abundance
of flower-visiting bees (C. arabica: 90% when
20 bee species were present and 60% when
only three species were present, Klein, et al.,
2003b; C. canephora: 95% when 20 or more
bee species were present and 70% when only
six species were present, Klein, et al., 2003c),
and the number of social bees species
decreased with distance to forest fragments
and the number of solitary bees increased with
light intensity (less shade) and greater quantities
of blossoms. Additionally, Klein, et al.,
(2003b,c) found that solitary bees had an
important participation in the pollination of C.
canephora shrubs, leading to higher levels of
fruit set that originated by members of social
bee assemblages.
These services can be translated into economic
advantages. For example, De Marco &
Coelho (op.cit.) found, as previously stated,
that coffee production increased 14.6% when