Apis florea in Europe: first report of the dwarf honey bee in Malta

Abstract

The Red dwarf honey bee (Apis florea), is a single-comb open-nesting member of the genus Apis
with a natural distribution area stretching from the Indomalayan realm on the east to the
Persian Gulf on the west. However, it is reportedly colonising new territories mainly due to
anthropogenic activities. Nowadays it can be found from Taiwan on the east, to Jordan, the
Arabian Peninsula and North-eastern Africa on the west. Here we present the first scientific
record of a fully established colony of A. florea in Europe. The colony was found on Malta, a crossway
of naval routes in the Mediterranean Sea. We documented the incident with photos, collected
samples of workers and drones and sequenced the mtDNA COI gene to confirm
assignment to A. florea. Also, we alert the competent authorities and the beekeeping community
to be vigilant and ready to undertake effective eradication measures. In the paper, we discuss
the risks and the potential consequences associated with the invasion of A. florea in Europe.

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Apis florea in Europe: first report of the dwarf
honey bee in Malta
Aleksandar Uzunov, Thomas Galea, Chao Chen, Giovanni Cilia, Cecilia Costa
& David Mifsud
To cite this article: Aleksandar Uzunov, Thomas Galea, Chao Chen, Giovanni Cilia, Cecilia Costa
& David Mifsud (21 Aug 2024): Apis florea in Europe: first report of the dwarf honey bee in
Malta, Journal of Apicultural Research, DOI: 10.1080/00218839.2024.2386888
To link to this article: https://doi.org/10.1080/00218839.2024.2386888
© 2024 The Author(s). Published by Informa
UK Limited, trading as Taylor & Francis
Group
Published online: 21 Aug 2024.
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NOTES AND COMMENTS
Apis florea in Europe: first report of the dwarf honey bee in Malta
Aleksandar Uzunov
a,b†
, Thomas Galea
c†
, Chao Chen
a,b
, Giovanni Cilia
d
, Cecilia Costa
d
and David Mifsud
e
a
State Key Laboratory of Resource Insects, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing,
China;
b
Ss. Cyril and Methodius University in Skopje, Faculty of Agricultural Sciences and Food, Skopje, Macedonia;
c
Breeds of
Origin Conservancy, _
Zebbu _
g, Malta;
d
CREA Research Centre for Agriculture and Environment, Bologna, Italy;
e
Division of Rural
Sciences and Food Systems, Institute of Earth Systems, University of Malta, Msida, Malta
ABSTRACTS
The Red dwarf honey bee (Apis florea), is a single-comb open-nesting member of the genus Apis
with a natural distribution area stretching from the Indomalayan realm on the east to the
Persian Gulf on the west. However, it is reportedly colonising new territories mainly due to
anthropogenic activities. Nowadays it can be found from Taiwan on the east, to Jordan, the
Arabian Peninsula and North-eastern Africa on the west. Here we present the first scientific
record of a fully established colony of A. florea in Europe. The colony was found on Malta, a cross-
way of naval routes in the Mediterranean Sea. We documented the incident with photos, col-
lected samples of workers and drones and sequenced the mtDNA COI gene to confirm
assignment to A. florea. Also, we alert the competent authorities and the beekeeping community
to be vigilant and ready to undertake effective eradication measures. In the paper, we discuss
the risks and the potential consequences associated with the invasion of A. florea in Europe.
ARTICLE HISTORY
Received 21 May 2024
Accepted 24 July 2024
KEYWORDS
Europe; Honey bees; Apis
florea; Malta; Invasive
species
Described by Fabricius (1787), the Red dwarf honey
bee (Apis florea), is a single-comb open-nesting mem-
ber of the genus Apis (Linnaeus, 1758). The species’
adaptability is well documented and reflected in its
native distribution area which covers different climatic
environments and habitats. Its range stretches from
the Indomalayan realm on the east to the Persian Gulf
on the west (Ruttner, 1988). A. florea is reported colo-
nising new territories (such as the Middle East and
eastern Africa) mainly due to anthropogenic activities
such as naval commerce and new dispersal corridors
resulting from man-made habitats (Silva et al., 2020).
Lord and Nagi (1987) were the first to report A. florea
in Africa when a population was detected in Khartoum
(Sudan). Currently, this honey bee has extended its distri-
bution range both on the east, where it was recorded on
the island of Taiwan and the west, having colonised
Jordan, the Arabian Peninsula and North-eastern Africa
(Haddad et al., 2008; Hepburn & Radloff, 2011; Shebl,
2017; Silva et al., 2020) and it is expected further extend
its distribution in the African continent (Abou-Shaara
et al., 2021, Dietemann et al., 2009, Silva et al., 2020).
Moreover, further colonisation towards the northwest
via Asia Minor and subsequently into Europe seems pos-
sible due to its establishment in Jordan (Haddad et al.,
2008) and the absence of major geographical and
environmental barriers in the region. Another dispersion
event could take place, through the intensive trade
across the Mediterranean basin, between North Africa,
the Middle East and southern Europe, the latter, charac-
terised by mild winters, a potentially suitable environ-
ment for the survival of A. florea. In addition, the spread
of this honey bee into new territories is further enhanced
by its prolific reproductive capacity and absconding
behaviour (Hepburn, 2011; Lindauer, 1957; Tirgari, 1971).
The present communication constitutes the first
scientific record and description of a fully established
colony (Figure 1) of A. florea in Europe. This colony
was found on Malta, the main island of the Maltese
archipelago in the Mediterranean Sea. Following an
online report on social media, the location (Apis
florea, Figure 2) was inspected, and the colony was
identified and photographed. The colony found was
well developed, with a typical single comb encircling
a branch (branch diameter 12 mm), and containing
both worker and drone cells. The comb was con-
nected to two branches. The length of the comb
(perpendicular to the earth’s surface) is 220mm, the
height is 150 mm and the width of the honey crest
is 90 mm. The queen was not found and the colony
seemed to be in an after-swarm state without brood
and food stores. However, no new or old-built queen
CONTACT Chao Chen chenchao@caas.cn
†
Aleksandar Uzunov and Thomas Galea shared the first authorship.
� 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/
licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not
altered, transformed, or built upon in any way. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the
author(s) or with their consent.
JOURNAL OF APICULTURAL RESEARCH
https://doi.org/10.1080/00218839.2024.2386888

cells were observed. The colony size was estimated
by counting over 2000 adult bees. No other swarms
were observed in the near vicinity.
Samples of worker and drone bees were collected
and stored in sample tubes containing 99% ethanol
for genetic analyses. Consequently, the colony,
alongside the section of the branch was removed
and sealed in a box with all adult bees being culled
using 99% ethanol. The comb was appropriately
stored, so that it would be protected from wax
moths. As soon as this colony was discovered and
positively identified as A. florea, it was immediately
removed and the competent authorities were
informed. The immediate removal of the colony was
a must due to the risk of swarming or absconding.
The empty comb was visually inspected and photo-
graphed. Thereafter, the comb with dead specimens
of A. florea was donated to the Biology Department
at the University of Malta.
The sampled worker and drone bees were used
for DNA barcoding, amplifying the cytochrome c
oxidase subunit I (COI) region of mtDNA (Folmer
et al., 1994). Briefly, thoraxes were dissected and
pooled from 3 workers and 3 drones. DNA from the
two pools were extracted using a commercial kit
Quick DNA Microprep Plus Kit (Zymo Research, Irvine,
CA, USA) as reported in Tiritelli et al. (2024).
Amplification of COI region was performed using
HotStarTaq Polymerase (Qiagen, Hilden, Germany)
and the PCR assay was performed on Applied
Biosystems
V
R
2720 Thermal Cycler (ThermoFisher
Scientific) (see Selis et al., 2024). The obtained ampli-
cons were visualised on a 1.5% agarose gel, purified
using ExoSAP-IT Express (ThermoFisher Scientific,
Waltham, MA, USA) and sequenced with Sanger
methodology through SeqStu-dio
TM
(ThermoFisher
Scientific) (Cilia et al., 2022).
The obtained sequences (631 bp) confirmed that
the samples belong to A. florea, and BLAST analysis
showed high similarity (97.62%) to A. florea (GenBank
Accession Numbers: A. florea workers PP905460, A.
florea drones PP905461).
Figure 1. Left: A. florea colony hanging on a tree branch of Acacia saligna, the Blue-leaved Acacia (photo source: Antoine
Bor _
g Bona _
ci), central: A. florea worker and drone bees (arrows), right: A. florea comb (lower right part of the comb was
damaged).
Figure 2. Map of Malta, the main island of the Maltese archipelago, with the location where A. florea colony was found, the
main Harbour and the Freeport.
2 A. UZUNOV ET AL.

The survival of A. florea colonies under the climatic
and environmental conditions present in the
Mediterranean basin is a probable scenario. Therefore,
if the identified colony has already swarmed, or if
there are other unidentified colonies, it is likely that A.
florea will become established in the Maltese Islands.
The lack of food and brood and the relatively small
population (ca. 2000 workers and drones) on a well-
developed comb having both worker and drone cells
indicate the probability of an after-swarm status.
Nevertheless, queen cells were not observed. For com-
parison, Seeley et al. (1982) reported more than 6000
workers as an average colony size for A. florea in
Thailand.
The establishment of A. florea in Malta would rep-
resent a serious risk to natural biodiversity due to
competition for resources and habitats, in a territory
that harbours numerous endemic species and where
anthropogenic pressures are already high. This is
also the case for other invasive species (Megachile
sculpturalis, M. disjuntiformis, Xylocopa pubescens and
X. aestunas) reaching the Mediterranean countries
(Bortolotti et al., 2018; Catania, 2023; Flaminio et al.,
2023; Ruzzier et al., 2020). Furthermore, it should be
noted that A. florea is a host of many harmful patho-
gens including Black Queen Cell Virus, possibly Thai
Sacbrood Virus, the parasitic mites Euvarroa sinhai
and Tropilealaps clareae, the common non-parasitic
facultative kleptophage Neocypholaelaps indica and
an unknown microsporidian (Delfinado-Baker et al.,
1989; Fries, 2011; Needham et al., 2001; Warrit &
Lekprayoon, 2011). As some of these pathogens are
known to switch hosts, the introduction of A. florea
into new areas can thus pose a real threat to the
health of Western honey bees (Apis mellifera) and
wild bees. Such invasion incident, combined with cli-
mate change and diminishing forage grounds, is
expected to increase the constraints on the endemic
A. m. ruttneri (Sheppard et al., 1997, Zammit-
Mangion et al., 2017) population in Malta, which
according to Uzunov et al. (2023) represents only a
small percentage of the current A. mellifera colonies
present in Malta.
The location where the colony of A. florea was
found is about 2.5 km in a direct line from the
Bir_
zebbu _
ga Freeport (Figure 2) where most cargo is
handled. Interestingly, in the commercial port of
Genova, Italy, in September 2022, a swarm of A.
florea was intercepted (and immediately destroyed)
on board of a cargo ship (https://agronotizie.imageli-
nenetwork.com/agricoltura-economia-politica/2022/0
9/16/apis-florea-chi-e-l-ape-asiatica-trovata-a-genova/
77048). Past A. florea introductions in the Middle
East and Africa together with the insularity of the
Maltese islands indicate that most likely the swarm
entered through naval traffic. This type of
transportation represents a possible route for the
introduction of alien invasive species, such as the
Dwarf honey bee into Europe. The present communi-
cation aims to alert the competent authorities and
the beekeeping community to be vigilant and fur-
ther monitor the potential presence of A. florea colo-
nies in the Maltese Islands and Mediterranean
coastal areas and to be prepared with effective
eradication measures.
Acknowledgements
The authors thank Mr Antoine Bor_
g Bona_
ci for alerting the
beekeeping community and allowing our team access to
his private site where A. florea colony was found. We also
thank Mr Arthur Lamoliere for his support in developing
Figure 2.
Disclosure statement
No potential conflict of interest was reported by the
author(s).
Funding
Key R&D Program of Shandong Province, China
(2023LZGC017); Agricultural Science and Technology
Innovation Program (CAAS-ASTIP-2024-IAR).
ORCID
Aleksandar Uzunov http://orcid.org/0000-0003-1240-
868X
Thomas Galea http://orcid.org/0009-0001-0762-5914
Chao Chen http://orcid.org/0000-0002-9582-1105
Giovanni Cilia http://orcid.org/0000-0002-5234-1240
Cecilia Costa http://orcid.org/0000-0001-9985-2729
David Mifsud http://orcid.org/0000-0001-9562-1077
Data availability statement
Sequences were submitted to Genbank under the acces-
sion numbers PP905460 (A. florea workers) and PP905461
(A. florea drones).
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