Locustacarus

 

HARMFUL | NOT HARMFUL | UNCERTAIN

internal parasite; feeds on hemolymph in tracheae and air sacs

Name and classification

Locustacarus Ewing, 1924

Taxonomy
Superorder Acariformes » Order Trombidiformes » Suborder Prostigmata » Infraorder Eleutherengona » Hyporder Heterostigmata » Family Podapolipidae » Genus Locustacarus

Type species
Locustacarus trachealis Ewing, 1924

Common synonyms
Bombacarus Stammer, 1951

Common names
tracheal mite

Diagnosis

Larviform female: coxal setae II extending beyond posterior margin of coxae II (Fig. 2). Coxae III with 1 pair of setae (Fig. 2).

Larviform male: aedeagus arises on anterior hysterosoma and extends freely to gnathosoma (Figs. 4, 6).

Adult female: Body sac-shaped. Only legs I present, legs II-IV absent (Fig. 3).

The family Podapolipidae is unique among other mites by having reproductive males and reproductive females at the larval stage. Hence larviform female (Figs. 1, 2) and larviform male (Figs. 4-7) have 3 pairs of legs. After insemination, larviform females molt to sac-like adult females with only 1 pair of legs (Fig. 3). Larviform males do not molt further. The number of legs can be different in other podapolipids.

Species identification

Locustacarus buchneri and L. trachealis (associated only with Orthoptera) can be separated using a key from Husband and Sinha, 1970. Locustacarus masoni (from locusts) should be identified using the original description.

Distribution

Holarctic region (Canada, USA, France, Germany, former Czechoslovakia, Denmark, Sweden, Poland, Russia, Armenia, and Japan); Oriental region (India); and Australian region (New Zealand)

Bee hosts

Locustacarus buchneri occurs primarily in the respiratory system of bumble bees (Bombus), but occasionally has been found on the European honey bee (Apis mellifera).

Host association level

Permanent

associated exclusively with bees or their close relative, wasps; cannot live without these hosts

Temporary

some life stages are associated with bees, while others are not

Facultative or opportunistic

can complete entire life cycle without bees or their close relative, wasps

permanent

Host associations, feeding, and dispersal

Locustacarus buchneri only

  • All stages live in the respiratory system (usually metasomal air sacs) of adult bumble bees (Bombus spp.). Females (larviform and adult) feed on the host hemolymph by piercing the tracheal walls. Males have poorly developed mouthparts. Sometimes small numbers of mites can be found in the nest or on pupae.
  • Larviform females are mobile and can disperse from one bee to another in the same nest. Adult females and males cannot disperse.

Biology

Only one species, Locustacarus buchneri, is known from bumble bees. Locustacarus trachealis and Locustacarus masoni are respiratory parasitizers of Orthoptera.

Locustacarus buchneri is an internal parasite of bumble bees occurring in tracheae and air sacs. Husband and Sinha reconstructed its life cycle based on their observations in the USA (Husband and Sinha, 1970). In late April, Bombus bimaculatus queens emerge from overwintering sites in the soil. Within a few days, larviform female mites (Figs. 1-2) in the tracheae enlarge as they ingest hemolymph, and their ovaries begin to function. Nearly one week after emergence of a queen bee, mite eggs hatch. Males have poorly developed mouthparts (Figs. 4-7), are short lived, and do not leave the host bee. Larviform female mites migrate to the tracheae of worker bees, attach to the tracheal walls, molt, and begin to enlarge. Adult females (Fig. 3) have only two legs and a greatly distended body and cannot leave the host. In the first week in July, male bees and new queen bees emerge. Males of Bombus (Psithyrus) spp., B. vagans, and other B. bimaculatus occasionally enter the nest and may bring in or take out larviform female mites in their tracheae. By early August, new queen bees have mated, left the nest, and some may have entered diapause at sites several inches below the ground. After the new queen bees leave the nest, few new workers are produced and older workers accumulate more and more mites. The number of mites in worker and male bees in August is sufficient to severely injure the bees. Diarrhea has been observed, and some bees are lethargic and no longer forage. Because worker bees, male bees, and the old queen bee die during fall, the only mites that survive to the following April are in the tracheae of young queens in diapause.

Bumble bees with Locustacarus buchneri had significantly reduced lifespans in the laboratory (Otterstatter and Whidden 2004).

This species was introduced to Japan with commercially bred Bombus terrestris from Belgium and Netherlands (Goka et al., 2001).

A single work reports this mite from the honey bee, Apis mellifera, in Poland (Tomaszewska, 1988).