The coccid-tending ant genus Acropyga Roger and its obligate associated myrmecophilous scale insect genus Eumyrmococcus Silvestri new to Italy (Hymenoptera: Formicidae; Hemiptera: Xenococcidae)
Author
Scupola, Antonio
Natural History Museum of Verona, Lungadige Porta Vittoria 9, 37139 Verona, Italy - scupolant @ outlook. it
scupolant@outlook.it
Author
Durante, Antonio
Natural History Museum of Salento, Strada Provinciale Calimera - Borgagne Km 1, 73021 Calimera (LE), Italy - antonio. durante @ msns. it - francesco. giannuzzi 90 @ gmail. com
antonio.durante@msns.it
Author
Giannuzzi, Francesco
Natural History Museum of Salento, Strada Provinciale Calimera - Borgagne Km 1, 73021 Calimera (LE), Italy - antonio. durante @ msns. it - francesco. giannuzzi 90 @ gmail. com
antonio.durante@msns.it
Author
Pellizzari, Giuseppina
Università degli studi di Padova, Dipartimento DAFNAE - Agripolis, Viale dell’Università 16, 35020 Legnaro (PD), Italy - giuseppina. pellizzari @ unipd. it
giuseppina.pellizzari@unipd.it
text
Fragmenta entomologica
2022
2022-05-15
54
1
89
94
http://dx.doi.org/10.13133/2284-4880/722
journal article
10.13133/2284-4880/722
2284-4880
8148219
Eumyrmococcus corinthiacus
Williams, 1993
Eumyrmococcus corinthiacus
belongs to the family
Xenococcidae
Tang, 1992
, a family of subterranean, obligate myrmecophilous mealybugs, characterized by unique morphological and biological traits.
The family is composed of 3 genera:
Eumyrmococcus
(20 species),
Neochavesia
(8 species), and
Xenococcus
(5 species). Their systematic position has been controversial because of their peculiar morphological and biological characteristics. For a long time, xenococcids were considered to belong to the
Pseudococcidae
, but they differ from pseudococcids in many morphological characters: e.g., the females do not have ducts, pores or ostioles; antennae have only 2 or 4 segments; eyes are absent; the anal ring lacks pores; the anal lobes have long setae; and the males are small, larva-like, apterous and without eyes, and the legs and antennae are strongly reduced (
Hodgson 2012
; Gavrilov Zimin 2018). Moreover, the female developmental cycle of some Xenococcinae (e.g.,
Neochavasia
species and
E. smithi
Silvestri
) is characterized by the presence of a quiescent pupal stage in the third instar (
Williams 1987
, 2004; Kishimoto-Yamada et al. 2015) whereas in other mealybug families this is a trophic stage.
Fig. 7 –
Subgenital plate of adult male
Acropyga paleartica
.
Tang (1992)
erected the tribe
Xenococcini
for these peculiar scale insects, in the subfamily
Rhizoecinae
(
Pseudococcidae
).
Hodgson (2012)
, based on male morphology, concluded that
Rhizoecinae
mealybugs were separate from the
Pseudococcidae
and elevated them to family
Rhizoecidae
, containing two subfamilies:
Rhizoecinae
Williams and Xenococcinae Tang.
Danzig & Gavrilov-Zimin (2014)
subsequently elevated Xenococcinae to family rank (
Xenococcidae
). This position was explained in detail by
Gavrilov-Zimin (2018)
, and the family was also recognised based on male morphology (
Hodgson 2020
;
Garcia Morales et al. 2016
).
Eumyrmococcus
females have a large head and thorax, abdomen rather tapering and, in profile, curved upwards.
Eumyrmococcus
species
feed on the phloem of plant roots and live underground in ant-nest tunnels of
Acropyga
spp.
ants. As discussed above, the species
E. corinthiacus
is associated to the ant
Acropyga paleartica
.
Based on the description and key by
Williams (1993
,
1998
),
Eumyrmococcus corinthiacus
is easily identified by having 4-segmented antennae and 3 thick setae on each anal lobe, with 2 setae longer and stouter than the other. The longer setae each have the apical part curved, like a hook.
So far,
E. corinthiacus
was known only from the
type
locality (Perachora, Corinth,
Greece
). The present record of
E. corinthiacus
in
Apulia region
is the first for
Italy
and the second in Europe. As it is known that
E. corinthiacus
and the ant
A. palearctica
are obligate symbionts, it is likely that
E. corinthiacus
is also present in Greek locations where only the ant
A. paleartica
has been recorded so far.
Acknowledgements
– We thank Gillian Watson (Natural History Museum, London) who kindly read the text and revised English language, and two anonymous referees for their valuable comments. Many thanks to Prof. Giacomo Santini (University of Florence) for his valuable advice on the study of the samples, and Gabriele Pellegrino (MSNS) for his kind help in collecting material.