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Hawthorn - mint aphidOn this page: Identification & Distribution Biology & Ecology Other species on the same host
Identification & Distribution:The aptera of Ovatus crataegarius is yellow-green to apple-green, sometimes mottled with darker green markings. The antennae are curved, and about 1.2-1.5 times the length of the body. The pale siphunculi are 1.7-2.6 times as long as the tongue-shaped cauda. The body length of apterae ranges from 1.5-2.0 mm. The alate has a green abdomen with darker green patches.
On their primary host, hawthorn, Ovatus crataegarius fundatrices and apterae are morphologically indistinguishable from Ovatus insitus, a sibling species that host alternates from hawthorn to gipsywort (Lycopus europaeus). However the spring migrant winged forms of Ovatus crataegarius have fewer secondary rhinaria (22-49) on their antennae than those of Ovatus insitus (which have 60-83). Their oviparae also have fewer pseudosensoria on their hind tibiae than those of Ovatus insitus.
The primary host of the hawthorn - mint aphid is hawthorn (Crataegus) and, less commonly, apple (Malus) or quince (Cydonia). In summer it host alternates to mint (Mentha) where it can reach pest status. In warmer climates Ovatus crataegarius may occur as an anholocyclic form on mint, overwintering viviparously near the ground. Ovatus crataegarius has a near worldwide distribution from Europe and the Middle East to Central Asia, India, Pakistan, parts of Africa, the USA, Canada and Brazil.
Biology & Ecology
OriginMüller (1980) considers the origin and subsequent evolution of Ovatus crataegarius and Ovatus insitus. They represent two sibling species, the sexuales of which encounter each other on mutual primary hosts. Comparisons have shown the fundatrices of the two species, as well as their apterous alienicolae (viviperae on the secondary host), to be morphologically indistinguishable. In the other morphs the range of variation of by far the most characters overlap to a high extent, or appear practically identical. Good distinguishing characters exist in the emigrant alatae and in the oviparous females. The emigrant alatae of Ovatus insitus show a higher number of rhinaria on the antennae than those of the other species. It is thought this character reflects the necessity of locating the alternative summer hosts. These are Mentha species, in Ovatus crataegarius, and Lycopus europaeus, in Ovatus insitus. The oviparous females of Ovatus insitus bear on their hind tibiae a significantly higher number of pseudosensoria. The differences in these sex pheromone producing organs may be responsible for the premating reproductive isolation between the two aphids.
A critical examination leads to the conclusion that almost certainly the genesis of these two species is not allopatric (evolved in geographic isolation). But some authorities consider a sympatric (non-isolated) mode of origin, as a result of occupying ecological niches, is virtually impossible too. The most plausible mode of speciation would be that mutational changes in feeding behaviour and in the efficiency for surviving on a new host plant happened. The author argues that such changes can bring about enough isolation for sympatric speciation.
Life cycleIn Britain during spring Ovatus crataegarius can be found commonly on hawthorn (see picture below of immatures on hawthorn), and less commonly on apple.
The leaves of the primary host normally harden-up in summer and their levels of soluble nitrogen drop. The aphids respond by developing alatae (see picture below) which migrate to mint.
However, anything which delays the drop in available nutrients delays their departure. Cichoka & Lubiarz (2012) showed that Ovatus crataegarius populations appeared in apple orchards in large numbers if the trees were pruned. We have also found that Ovatus may remain on hawthorn if they feed inside old Dysaphis galls (see picture below). The galls remain green probably because of the release of cytokinins by the original gall-maker.
Those aphids that do migrate to mint can again be distinguished by their long curved antennae (see picture below).
Leonard (1963) describes the distribution and habits of Ovatus crataegarius in America. Goszczynski et al. (2016 ) found Ovatus crataegarius and Ovatus mentharius on mint plants in greenhouses in Poland. Ovatus crataegarius was an anholocyclic form that overwintered in the greenhouses.
Jaskiewicz & Slawinska (2004) monitored aphid populations on five Crataegus media trees in park and street sites from 1999-2001 in Lublin, Poland. Four aphid species were found : Aphis pomi, Ovatus crataegarius, Rhopalosiphum insertum (= Rhopalosiphum oxyacanthae) and a Dysaphis species. More aphid species, and larger numbers of aphids, were found on trees in the street-site than in the park-site. Generally Aphis pomi and Dysaphis were commonest, followed by Ovatus crataegarius and Rhopalosiphum oxyacanthae. Ovatus crataegarius (see picture below) was found on hawthorn in May-June through to late July, reaching maxima varying from 7 to 56 aphids per 5 shoots.
In one year the same species (see picture below) was observed again from the end of September through to October.
Ovatus crataegarius may get attacked by Entomophthora when on hawthorn (see picture below).
Goszczynski et al. (2016 ) recommended use of the braconid parasitoid Aphidius colemani, the cecidomyiid Aphidoletes aphidimyza, and the neuropteran Chrysoperla carnea for biological control of Ovatus crataegarius in greenhouses in Poland.
Other aphids on same host:
We will only consider common hawthorn (Crataegus monogyna) here, but Ovatus crataegarius also occurs on several other related plants.
Blackman & Eastop list 16 species of aphid as feeding on common hawthorn (Crataegus monogyna) worldwide, and provide formal identification keys.
Of those aphid species, Baker (2015) lists 15 as occurring in Britain on this primary host: Aphis fabae, Aphis gossypii Aphis pomi, Aphis spiraecola, Aulacorthum solani, Dysaphis angelicae, Dysaphis apiifolia, Dysaphis crataegi, Dysaphis lauberti Dysaphis ranunculi, Ovatus crataegarius, Rhopalosiphum oxyacanthae, Ovatus insitus, Prociphilus pini and Rhopalosiphum rufulum.
Blackman & Eastop list 11 species of aphid as feeding on garden mint (Mentha spicata) and water mint (Mentha aquatica) worldwide, and provide formal identification keys.
Of those aphid species, Baker (2015) lists 10 as occurring in Britain on mint: Aphis fabae, Aphis gossypii Aulacorthum solani, Kaltenbachiella pallida, Macrosiphum euphorbiae, Myzus ascalonicus, Myzus ornatus, Myzus persicae, Ovatus crataegarius and Ovatus mentharius.