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Cypress pine aphid, Thuja aphidOn this page: Identification & Distribution Biology & Ecology: Population dynamics Ant attendance Other aphids on the same host Damage & Control
Identification & Distribution
Adult apterae of Cinara tujafilina are reddish-brown with a dorsal pattern of bluish-white wax, and two dark brown divergent curved bands running from head to about the level of the siphunculi (see first & second picture below). The terminal process of the antenna is very short and stumpy, about as long as its basal width (cf. Cinara cupressi and Cinara fresai which have the terminal process of the antenna distinctly longer than its basal width). The hind femora are pale, and the hind tibiae are only dark at their apices, though sometimes have very localised pigmentation at their tibio-femoral joints (cf. Cinara cupressi and Cinara fresai which have the distal parts of hind femora and bases of hind tibiae dusky or dark). The body length of the adult aptera of Cinara tujafilina is 1.7-3.5 mm.
First image above copyright Boogoljub Milošević, all rights reserved.
The alate Cinara tujafilina (see third picture above) is also reddish-brown with bluish-white wax. The base of antennal segment VI of the alate has 6-16 hairs, but rarely less than 8 (cf. Cinara cupressi alatae where the base of that segment has 5-7 hairs). The antennal terminal process of the alate is about as long as its basal width (cf. Cinara juniperi and Cinara fresai alatae which have the terminal process distinctly longer than its basal width). The fourth rostral segment (RIV) of the alate has 4-8 accessory hairs (cf. Cinara cupressi alatae where RIV has 2-4 hairs). The hind tibiae of the alate are dark only at their apices (cf. Cinara juniperi and Cinara fresai alatae whose hind tibiae are entirely dark).
Cinara tujafilina can be found on many genera of Cupressaceae including Chamaecyparis, Cupressus, Juniperus and Thuja orientalis. They feed on foliated branches, on the undersides of branches near the trunk - or, in midsummer, on roots. The cypress pine aphid is sometimes attended by ants. It is believed to be almost entirely parthenogenetic, overwintering on the roots in colder climates, although oviparae and males have been recorded. Cinara tujafilina is virtually cosmopolitan, although it is commoner in warmer climates such as around the Mediterranean.
Biology & Ecology
Durak (2014) examined the overwintering strategy of Cinara tujafilina in Poland. Cinara tujafilina is an anholocyclic species infesting mainly the twigs of Thuja orientalis. It rarely (if ever) produces eggs. Instead, in winter, it produces three to five generations that infest the roots of the host plant. The main factor that triggers Cinara tujafilina to change the feeding site is temperature. At 13 °C, these aphids migrate from leaves to the main trunk. At 0°C, first and second instar nymphs descend underground and feed on roots. The growth, life span and fecundity of the winter generations do not differ significantly from the generations produced in spring and autumn. The third root-infesting generation shows the highest developmental parameters, such as the highest fecundity, a longer reproduction period and no post-reproduction, indicating the optimal adaptation to living in soil in winter. The life cycle strategy enables anholocyclic populations to survive winter and to infest plants very early in spring, which gives them an advantage over species that overwinter as eggs.
Image above copyright Boogoljub Milošević, all rights reserved.
Furuta (1988) studied the population dynamics of Cinara tujafilina in Japan. The aphid deposits larvae parthenogenetically throughout the winter in Tokyo. The theoretical developmental threshold and reproductive threshold were estimated to be at 9.2 and 3.5 °C. The aphids born in winter required two months to develop and continued to deposit larvae for 2-4 months. They had smaller intrinsic rates of increase, but had greater longevity and laid more larvae than those born in spring. Thus, aphid numbers increased from autumn to winter, and the larger populations in autumn were followed by higher peaks the next spring. At this latter time, the combined impact of syrphids, and disease caused by a Conidiobolus species greatly reduced the aphid populations. These populations thus tended to have alternate abundant and scarce years. When syrphids were removed, however, a high peak number was realized every spring. It was concluded that the syrphids, which showed an aggregative response to large aphid populations, were responsible for the alternate abundant and scarce aphid cycles. Large number of aphids infested the same trees for at least three years, and the condition of their host trees did not seem to have played an important role in the dynamics of the aphid populations. Disease epidemics usually killed the aphids before they had any major adverse effects on the host trees.
Durak et al. (2015) sought to assess whether anti-predator protection provided by ants is the only benefit for aphids, or whether there are other important benefits. They used video recordings to analyse the ant-aphid interactions in the absence of predators, and obtained ant time-budgets at different times of the day. They also tested if an aphid colony can survive without ant attendance in an environment free from predators, and assessed how much ant attendance is needed to maintain an aphid colony in good condition. They found that aphids of the species Cinara tujafilina were not able to survive without ant attendance even with no predation pressure. Extinction was caused by the excessive honeydew that covered aphids and their surroundings. They also found that ants cleaning aphids was the most frequent and time-consuming activity in ant-aphid interactions. Despite this, ants interacted with aphids for less than 5% of their total time-budget. They concluded that surprisingly little ant effort is needed to maintain an aphid colony in good condition.
Copyright Mihajlo Tomić, all rights reserved.
Lasius niger attending Cinara tujafilina nymphs. Copyright Carlos Delgado under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Starý (2005) notes that Pauesia hazratbalensis is the only known parasitoid of Cinara tujafilina. Pauesia hazratbalensis is originally a montane species (from Kashmir, Kirghizia), but has proved its capability to also occur in lowland areas, having been reared from Cinara tujafilina on Thuja orientalis in a lowland area of Tehran, Iran. (For its identification see Rakhshani et al., 2012.) Pauesia hazratbalensis is potentially useful in the biocontrol of Cinara tujafilina in the Mediterranean and other parts of the world.
Other aphids on same host:
Blackman & Eastop list 28 species of aphid as feeding on junipers (Juniperus spp.) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 7 as occurring in Britain (Show British list).
Damage and control
Cinara tujafilina is considered a minor pest in some states in the USA and parts of South America. In Oklahoma State it has been reported to cause foliage to turn brown and to kill branches of arborvitae (Thuja spp.) and Italian cypress (Cupressus sempervirens) (see Oklahoma State University). The aphids may also have considerable annoyance value as they produce large amounts of honeydew which drips on to cars and sidewalks, and attracts flies and wasps. Control is not usually considered worthwhile (or practical). In Argentina the aphid particularly attacks Austocedrus chilensis and Thuja spp. (Delfino & Binazzi, 2005).