Shahmshad Ahmed Khan Science Reviews - Biology, 2023, 2(4), 1-6
1
Review of the Role of Bees as Ecosystem Engineers in
Nature
Shahmshad Ahmed Khan
1
, PhD candidate
1
University of Sargodha, Pakistan
Corresponding author: shamshadahmeduca@gmail.com
https://doi.org/10.57098/SciRevs.Biology.2.4.1
Received November 08, 2023. Revised November 18, 2023. Published online December 28, 2023.
Abstract: Bees are a highly important group, providing a multitude of services to ecosystems, most notably
through pollination. While much of the research on bees has traditionally focused on their role in pollinating a
variety of wild and cultivated crops, this review paper expands the discourse by examining their functions as
ecosystem engineers. Traditional definitions of ecosystem engineers exclude pollinators due to their non-
physical modifications of habitats for other species. However, contemporary studies challenge this perspective,
recognizing pollinators as integral ecosystem engineers who offer a range of direct and indirect ecological
services. For instance, bees’ pollination activities lead to the formation of dry fruits that subsequently serve as
shelters for various organisms. In addition, ground-nesting bees modify soil composition through mechanisms
such as aeration and bioturbation. This review aims to elucidate the transformative impact bees have as
ecosystem engineers, thereby enhancing our understanding of their ecological importance.
Keywords: Ecosystem engineers, Ecosystem function, Habitat modification, Soil Bioturbation, Ground nesting
soil
Introduction
Ecosystem engineers are organisms that modulate
the availability of resources for other species, either
directly or indirectly, by altering the physical state
of biotic and abiotic materials within their ecosys-
tem (Jones, Lawton, & Shachak, 1994). These engi-
neers, through modifications of abiotic conditions,
instigate changes in the biological responses of res-
ident species, thereby influencing ecosystem func-
tioning. Ecosystem functioning encompasses both
physiochemical and biological processes within the
ecosystem, which are closely associated to human
well-being. This connection is evident in services
such as carbon sequestration, productivity, and nu-
trient cycling (Byers, 2022).
Overview of Bees as Ecosystem Engineers
Mills, Soulé, and Doak (1993) identified five catego-
ries of keystone species, among which includes key-
stone habitat modifiers or ecosystem engineers
(Lawton & Jones, 1995). These engineers are further
classified as either autogenic or allogenic (Jones et
al., 1994). Autogenic engineers modify environ-
ments with their physical structures, such as living
or decaying tissues. Conversely, allogenic engineers
transform environments by manipulating biotic or
abiotic components through various activities
(Jones et al., 1994; Jones, Lawton, & Shachak, 1997).
However, the complexity inherent in species rich-
ness makes classifying certain organisms challeng-
ing. For instance, pollinators like bees were not tra-
ditionally considered ecosystem engineers by Jones
et al. (1994) because they primarily modulate re-
sources supply for seed and fruit consumers. None-
theless, recent perspectives, such as those put forth
by Wilby (2002), suggest expanding the term ‘eco-
system engineering’ to include organisms whose
actions create or modify habitats, even if their influ-
ence does not align with traditional definitions of
engineering (Casas-Crivillé & Valera, 2005). Under
this broader definition, pollinators like bees can in-
deed be considered ecosystem engineers due to
their direct and indirect impacts on ecosystems
(Cardoso, Rezende, Caetano, & Oliveira, 2023;
Casas-Crivillé & Valera, 2005).
Shahmshad Ahmed Khan Science Reviews - Biology, 2023, 2(4), 1-6
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Bees form a monophyletic group of insects with
over 20,000 described species across seven families,
inhabiting a diverse array of latitudes and terres-
trial ecosystems (Patel, Pauli, Biggs, Barbour, & Bo-
ruff, 2021). Globally, both wild bees and managed
honeybees are economically significant as pollina-
tors (Kremen & Chaplin-Kramer, 2007; Kremen,
James, & Pitts-Singer, 2008). Their efficient pollen
transport, reliance on floral resources, and social be-
haviors, from semi-social to eusocial classifications,
enable them to be prolific pollinators for a wide
spectrum of plant species (Klein, Boreux, Fornoff,
Mupepele, & Pufal, 2018; Ollerton, 2017). Bees are
responsible for pollinating more than 90% of the
world’s flowering crops (Klein et al., 2007). In addi-
tion to increasing crop yields (Aizen et al., 2019;
Aizen & Harder, 2009), bees enhance the nutritional
value and quality of fruits and vegetables (Ahmad
et al., 2021; Khan et al., 2022; Klatt et al., 2014), indi-
rectly mitigating food waste associated with aes-
thetic and quality imperfections (Gunders & Bloom,
2017). The crucial role of wild and managed bees in
pollinating wild plants in forest ecosystems is also
well-documented (Senapathi et al., 2015).
In this review, we aim to understand the role of bees
as ecosystem engineers and explore their ecological
functions across various ecosystems. While tradi-
tionally pollinators, specifically bees, were not
acknowledged as ecosystem engineers due to their
focus on resource provisioning (Jones et al., 1994),
recent studies indicate that pollinator bees might
fulfill the role of ecosystem engineers providing di-
verse environmental services. Bees also serve as bi-
oindicators for contaminants resulting from in-
creasing anthropogenic activities. The honeybee
(Apis mellifera), in particular, is recognized as a val-
uable bioindicator due to its close association with
the ecosystems it inhabits (Sadeghi, Mozafari, Bah-
mani, & Shokri, 2012). Bees encounter various con-
taminants during foraging, in flight, and through
nectar and pollen consumption (Ruschioni et al.,
2013). Analysis of the honeybees can reveal the
presence of elements such as Cu, Cr, Zn, Mn, and Fe
concentrations, which correlate with seasonal
changes and agricultural practices (Skorbiłowicz,
Skorbiłowicz, & Cieśluk, 2018).
Bees' Role in Pollination and Biodiversity
Pollination is important for the stability of natural
ecosystems and the production of various vegeta-
bles and crops, forming a critical link between agri-
culture and the cycle of life. So the process of
pollination significantly contributes to economic
improvement (Gill et al., 2016; Hristov, Neov,
Shumkova, & Palova, 2020). The term ‘pollination’
is the transfer of pollen from the male anthers to the
female stigma, either within the same flower or be-
tween different flowers on same or on different
plants.
Over 75% of food crops are partially or completely
dependent on animal pollinators, with pollinating
bees playing a crucial role in the production of
fruits, vegetables, coffee, cocoa, and almonds (Klein
et al., 2007). Pollinators such as bees are also key in
supporting biodiversity, as evidenced by the posi-
tive correlation between plant and pollinator diver-
sity (Ollerton, 2017). The abundance and species
richness of pollinators in an area are considered as
an indicator of the overall health of that ecosystem.
Certain crops, including cherries, blueberries, and
apples, solely rely on bee pollinators for up to 90 %
of their yield, indicating the interdependence be-
tween bee pollinators and plant diversity (Biesmei-
jer et al., 2006).
Pollination as Ecosystem Engineering
For pollinators to function as ecosystem engineers,
certain conditions must be met. Firstly, the plant
species must require biotic factors for pollination.
Secondly, the resultant fruits should be of a dry type
that is not consumed by frugivores and predators,
allowing them to remain in the environment for an
extended period. Thirdly, post-seed dispersal, these
fruits should create habitats for other organisms
(Cardoso et al., 2023). In this scenario, a plant acts
as an autogenic engineer, modifying the environ-
ment through its physical structures. Conversely,
the pollinator serves as an allogenic engineer, effect-
ing change through various activities (Figure 1)
(Cardoso et al., 2023).
Habitat Construction and Maintenance
Bees from the Andrenidae, Fideliidae, Halicitidae,
Melittidae, Oxaeidae, and Stenotritidae families
build their nests underground across wide range of
habitats. These habitats include weathered sand-
stone, prehistoric walls, dense clay, and sandy
dunes of deserts and beaches (Custer, 1928; Roubik
& Roubik, 1992; Stephen, 1965). Most species prefer
soils that are well-drained, ranging from horizontal
to vertical orientations for nesting (Linsley, 1958).
However, species such as Epicharis, Dasypoda, and
Nomia, are well-known for building nests in areas
prone to submersion. In populated areas, solitary