Platyhelminthes

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The phylum Platyhelminthes includes two classes of worms that involve ants: the cestodes (tapeworms) and the trematodes (flukes and blood flukes). These two groups have complex life-cycles, with mature stages that live as parasites in the digestive systems of fish or land vertebrates, and intermediate stages that infest secondary hosts, including ants.

Cestodes

All cestodes are parasites of vertebrates; many have complex life histories, including a stage in a definitive (main, vertebrate) host in which the adults grow and reproduce, often for years, and one or two intermediate stages in which the larvae develop in other hosts (typically arthropods or other vertebrates). The adults live in the digestive tracts of vertebrates, while the larvae often live in the bodies of other animals.

Commenting on cestode infections in Manica bradleyi, Prebus (2023) were uncertain of the details of parasite transmission, but speculated that workers collect bird feces containing cestode eggs while foraging and feed these to its larvae via trophallaxis, which has been observed in other ants (Horsfall, 1938). Development of infected individuals is likely disrupted by nutrient deficiency, potentially causing the morphological modifications observed in infected workers.

Known Ant Hosts

Ant Cestode Species Locality Source Notes
Brachyponera chinensis Raillietina kashiwarensis Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Brachyponera sennaarensis Raillietina tetragona Sudan Mohammed et al., 1988; Laciny, 2021
Carebara Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest; as ''Pheidologeton'' sp.
Crematogaster lineolata Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Forelius pruinosus Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Formica rufa Raillietina friedbergeri Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Harpagoxenus sublaevis Type 2 (Choanotaenia unicoronata?) South Tyrol, Italy Buschinger, 1973; Laciny, 2021
Lasius niger Mesocestoides sp. Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Leptothorax Choanotaenia crateriformis Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Leptothorax acervorum Choanotaenia unicoronata South Tyrol, Italy; Bavaria, Germany Buschinger, 1973; Peru et al., 1990; Laciny, 2021
Manica bradleyi Raillietina sp. California, United States Prebus et al., 2023
Monomorium Cotugnia digonopora Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Monomorium Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Monomorium floricola Cotugnia digonopora Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Monomorium floricola Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Monomorium indicum Cotugnia digonopora Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Monomorium indicum Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Monomorium indicum Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Myrmica rubra Davaineidae (Raillietina urogalli??) Scotland Muir, 1954; Laciny, 2021
Myrmica rubra Raillietina urogalli Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Myrmica scabrinodis Davaineidae (Raillietina urogalli??) Scotland Muir, 1954; Laciny, 2021
Myrmica scabrinodis Raillietina urogalli Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole bergi Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole bicarinata Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole bicarinata Raillietina georgiensis Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole bicarinata Raillietina georgiensis Georgia, United States Muir, 1954; Laciny, 2021 as ''Pheidole vinelandica''
Pheidole bicarinata Raillietina loeweni Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole bicarinata Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole dentata Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole fervida Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole jucunda fossulata Cotugnia digonopora Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole jucunda fossulata Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole jucunda fossulata Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole nodus Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole pallidula Raillietina circumvalata Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole pallidula Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Pheidole soritis Raillietina loeweni Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest; as Pheidole sitarches campestris
Solenopsis molesta Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tapinoma sessile Mesocestoides sp. Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Temnothorax affinis Anomotaenia brevis Germany Scharf et al., 2012; Laciny, 2021
Temnothorax affinis Dilepididae (type 1(?)) Germany Buschinger, 1973; Laciny, 2021
Temnothorax aveli Dilepididae (type 1(?)) Germany Buschinger, 1973; Laciny, 2021
Temnothorax lichtensteini Choanotaenia crateriformis Spain Espadaler & Riasol, 1983; Laciny, 2021
Temnothorax nylanderi Anomotaenia brevis Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Temnothorax nylanderi Anomotaenia brevis France Gabrion et al., 1976; Laciny, 2021
Temnothorax nylanderi Anomotaenia brevis France (lab colony) Trabalon et al., 2000; Laciny, 2021
Temnothorax nylanderi Anomotaenia brevis Germany Scharf et al., 2012; Beros et al., 2015; Feldmeyer et al., 2016; Laciny, 2021
Temnothorax nylanderi Anomotaenia sp. Spain Espadaler et al., 2011; Laciny, 2021
Temnothorax nylanderi Choanotaenia crateriformis Spain Espadaler & Riasol, 1983; Laciny, 2021
Temnothorax nylanderi Dilepididae (type 1(?)) Germany Buschinger, 1973; Laciny, 2021
Temnothorax parvulus Dilepididae (type 1(?)) Germany Buschinger, 1973; Laciny, 2021
Temnothorax rugatulus Dilepididae unspecified (cf. Anomotaenia) Arizona/New Mexico, United States Heinze et al., 1998; Laciny, 2021
Temnothorax unifasciatus Anomotaenia sp. Spain Espadaler et al., 2011; Laciny, 2021
Temnothorax unifasciatus Choanotaenia crateriformis Spain Espadaler & Riasol, 1983; Laciny, 2021
Temnothorax unifasciatus Dilepididae (type 1(?)) Germany Buschinger, 1973; Laciny, 2021
Tetramorium Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium caespitum Raillietina caucasica Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium caespitum Raillietina circumvalata Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium caespitum Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium caespitum Raillietina fedjuschini Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium caespitum Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium semilaeve Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium simillimum Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium simillimum Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium tortuosum Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium tortuosum Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium tsushimae Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest; as Tetramorium caespitum jacoti
Tetramorium tsushimae Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest; as Tetramorium caespitum jacoti
Tetramorium wroughtonii Raillietina echinobothrida Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Tetramorium wroughtonii Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Trichomyrmex destructor Cotugnia digonopora Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Trichomyrmex scabriceps Raillietina tetragona Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest

Trematodes

Trematodes are primarily internal parasites of molluscs and vertebrates. Most trematodes have a complex life cycle with at least two hosts. The primary host, where the flukes sexually reproduce, is a vertebrate. The intermediate host, in which asexual reproduction occurs, is usually a snail, but includes several species of ants as well.

The best studied example is Dicrocoelium dendriticum, the lancet liver fluke. Adults of Dicrocoelium dendriticum are found in the bile ducts of sheep, cattle, pigs, deer, cottontail rabbits, and woodchucks, while earlier life stages inhabit snails and ants. Fluke eggs are eliminated in the feces of their vertebrate hosts and are ingested by terrestrial snails. Cercaria (the free-swimming larval stage) develop in the snails, are secreted in the snail’s mucus or slime ball, and are ingested by ants. Once within the ant the parasites develop in two areas of the ant’s body, the brain and the abdomen. Those in the brain cause the ant to disperse to the tips of grass blades or other vegetation at dusk, lock their mandibles to the vegetation, and remain there until dawn (this behaviour is called summiting behavior). In this position they are most likely to be eaten by herbivores (the fluke's primary host) in the early morning. This behaviour will be repeated every night until the ant is eaten by a vertebrate host in which the parasite can fully mature and complete its life cycle.


  • Formica aserva worker infected with the lancet liver fluke, Dicrocoelium dendriticum. (A) False-coloured 3D volume rendering in sagittal section. (B) Micro-CT-based virtual sagittal section of an ant gaster harbouring 6 encysted metacercariae. (C) Micro-CT-based virtual sagittal section of an ant gaster harbouring 98 encysted metacercariae. (D) False-coloured 3D volume rendering of an infected ant gaster in sagittal section, showing scar-like marks (arrow) on the crop surface. Abbreviations: br, brain; cr, crop; emc, encysted metacercaria; nmc, non-encysted metacercaria. From Martin-Vega et al., 2018, Fig. 2.
  • Diagrammatic representation of life cycle stages of Dicrocoelium dendriticum. A Final host: chiefly sheep and cattle; humans are incidental (“accidental hosts”). 1 Sexually mature liver fluke (see under III). 1 a Egg with a fully formed miracidium. B Intermediate host: land snails (Helicella, Zebrina). 2 Miracidium which has emerged from a snail. 3 a The youngest sprorocyst. b The oldest sporocyst stage (mother sporocyst). c Daughter sporocyst. d A single cercaria (the so-called Cercaria vitrina). e Shell of Helicella ericetorum. f Shell of Zebrina dendrita. C 2. Intermediate hosts: ants. 4 a Slime balls laid by the snail on grass stem. 4 b An isolated (single) slime ball laid by the snail. 5 a An ant eating slime balls. 5 b Mature metacercariae from ants. (I) A miracidium emerging. (II) “Cercaria vitrina”. (III) A sexually mature liver fluke. From Piekarski, 1963.
  • Typical life cycle of a Dicrocoelium spp.
  • Dicrocoelium life cycle, the simplified version.

Known Ant Hosts

Ant Cestode Species Locality Source Notes
Camponotus compressiscapus Dicrocoelium hospes Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Camponotus herculeanus Brachylecithum mosquensis Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Camponotus pennsylvanicus Brachylecithum mosquensis Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Cataglyphis aenescens Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Cataglyphis aenescens Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Cataglyphis albicans Dicrocoelium lanceatum Armenia Arakelian et al., 1997 as ''Cataglyphis albicans armenia''
Cataglyphis bicolor Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica aserva Dicrocoelium dendriticum Canada (Alberta) van Paridon et al., 2017; Martin-Vega et al., 2018; Criscione et al., 2020
Formica cunicularia Dicrocoelium dendriticum Germany Hohorst & Graefe, 1961
Formica cunicularia Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Formica fusca Dicrocoelium dendriticum de Bekker et al., 2018
Formica fusca Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Formica gagates Dicrocoelium chinensis Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica gagates Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica lugubris Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica mesasiatica Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica picea Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica polyctena Dicrocoelium dendriticum Denmark Botnevik et al., 2016; de Bekker et al., 2018
Formica pratensis Dicrocoelium dendriticum de Bekker et al., 2018
Formica pratensis Dicrocoelium dendriticum Quevillon, 2018 encounter mode secondary; indirect transmission; transmission outside nest
Formica rufa Dicrocoelium dendriticum de Bekker et al., 2018
Formica rufa Dicrocoelium lanceatum Armenia Arakelian et al., 1997 Arakelian et al. (1997) note this infection is questionable
Formica rufibarbis Dicrocoelium dendriticum de Bekker et al., 2018
Formica rufibarbis Dicrocoelium dendriticum Germany Hohorst & Graefe, 1961
Formica rufibarbis Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Formica sanguinea Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Formica sanguinea Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Formica transkaucasica Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Lasius Dicrocoelium dendriticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest
Proformica pilosiscapa Dicrocoelium lanceatum Armenia Arakelian et al., 1997
Technomyrmex albipes Eurytrema pancreaticum Quevillon, 2018 encounter mode primary; indirect transmission; transmission outside nest

References