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Cinara hottesi

Blue-black spruce aphid

Identification & Distribution  Biology & Ecology 

Identification & Distribution:

The apterae of Cinara hottesi (shown below) are dull bluish-black in life. The dull black of the body is in sharp contrast to the mainly yellowish-orange appendages.

Image copyright Stephen McKechnie, all rights reserved.

There is no wax deposit on the body. The siphuncular cones are pigmented and much darker than the rest of the cuticle. The body length of is 3.0-3.5 mm.

Identification of Cinara hottesi can be confirmed microscopically using the following characters. The hairs on the outer side of the hind tibia are quite long (up to 0.12 mm) and markedly longer than the width of the hind tibia at midpoint (see the second image below). The second hind tarsal segment is about 0.28 mm. The last two rostral segments (RIV+V) are 0.24 to 0.36 mm in length. The third antennal segment has no secondary rhinaria. The hind tibia is quite long at about 1.80-1.85 mm.

 

Recent research suggests there may be three morphologically cryptic species currently classified under Cinara hottesi. (Foottit et al., 2009 ).

Cinara hottesi feeds on several species of spruce, especially white spruce (Picea glauca) and black spruce (Picea mariana). Oviparae and apterous males occur in September-October in Colorado. The species is widespread in North America.

 

Biology & Ecology:

Cinara hottesi is a good example of species that form large colonies. The eggs are deposited close together, usually on the needles of a few twigs only. The young nymphs cluster together immediately after hatching, forming groups on small branches. Small clusters change position several times, always moving to thicker parts of branches nearer the trunk. If they encounter other clusters they merge to form a larger group (Bradley, 1951 , 1961 ). By the time nymphs are half grown they usually form single large colony on the trunk.

Image copyright Stephen McKechnie, all rights reserved.

The colony continues to grow until it covers most of trunk and branches. Alate females are then produced which disperse to new host trees. Large numbers of alate females may remain resting on the needles for a day or two after the wings are fully developed. At this time alates drop off needles at slightest disturbance. Adult apterae also show the same predator escape response. After falling to the ground, the aphid walks to the tree and climbs it again.

The picture below shows that Cinara hottesi sometimes lives in multi-species colonies. The first picture below shows several immatures of a different species of aphid with extensive white wax markings mixed in with Cinara hottesi. The second picture below shows two matt black adult Cinara hottesi and three of the other species including two greeny-brown adults.

 

Images copyright Stephen McKechnie, all rights reserved.

We have yet to formally identify this second species, but it appears to be Cinara pruinosa an exceptionally variable species which often occurs with other Cinara species on spruce.

Cinara hottesi is strongly attended by a variety of ant species, such as in the colony below.

Image copyright Stephen McKechnie, all rights reserved.

Ant species recorded include Campanotus herculeanus, Formica subnuda, and Myrmica lobicornis. Colonies not attended have been observed to die out because of honeydew accumulation, so ant attendance is probably obligatory. Despite ant attendance various predators have been recorded preying on Cinara hottesi including larvae of the syrphids Syrphus vittafrons, Neomysia and Scymnus, larvae of the neuropteran Chrysopa californica and the mite Allothrombium. There may also be heavy predation by spiders.

Acknowledgements

We are indebted to Stephen McKechnie for specimins of Cinara hottesi, and several of the images above,

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994)  and Blackman & Eastop (2006)  supplemented with Blackman (1974) , Stroyan (1977) , Stroyan (1984) , Blackman & Eastop (1984) , Heie (1980-1995) , Dixon & Thieme (2007)  and Blackman (2010) . We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure  provided by Blackman & Eastop (2006).

Useful weblinks 

References

  •  Bradley, G.A. (1951). A field key to the species of Cinara (Homoptera: Aphididae) of Canada east of the Rockies. The Canadian Entomologist 83 (12), 333-335. Full text 

  •  Bradley, G.A. (1961). A study of the systematics and biology of aphids of the genus Cinara Curtis in Canada. PhD Thesis, McGill University, Montreal, Canada. Full text 

  •  Foottit R.G. et al. (2009). DNA barcodes to explore diversity in aphids (Hemiptera Aphididae and Adelgidae). Redia 92, 87-91. Full text 

 

Identification requests

Stephen McKechnie, 08/17/2014, Distribution of Cinara piceae

I have several Aphids in a vile with alcohol and I would like to have them identified. My location is White Fox, about 400 km. south of centre in the province of Saskatchewan, Canada.

Searching for Black Aphids brought me to your web site. From there I looked for Cinara on the Bug Guide site which only collects images from North America north of Mexico.

I added images to Bug Guide. 

Image(s) copyright Stephen McKechnie, all rights reserved.

The photograph [on Bug Guide] by Tom Murray in Worcester County, California, USA. also looks very similar to what I have on my spruce trees (Picea mariana). "The hind femora are reddish brown and black distally." Tom's image yes, not mine. Does age effect colour? Cinara piceae found in Russia and Argentina.

The effected trees are less than three meters tall. The red tag indicates the location of one colony.

Image(s) copyright Stephen McKechnie, all rights reserved.

 

Image(s) copyright Stephen McKechnie, all rights reserved.  

Bob, Influentialpoints: 09/01/2014

  • The aphids you sent us were definitely Cinara hottesi, not Cinara piceae. 

    Here is how we reached that conclusion:

    Of the 24 species (worldwide) known to occur on Picea mariana (Black Spruce) just 10 are Cinara species (Cinara abietis, braggii, costata, fornacula, hottesi, mariana, nigripes, nimbata, pruinosa, rara). Cinara piceae is not known on that host. However, aphids are always being found on additional hosts, so we only assumed the tree was a Picea sp..

    To allow for the possibility your aphids were an invasive or imported species, we identified your aphids using the Blackman & Eastop key (which covers world species on Picea).

    The main characteristics we measured were as follows:

    1. Width tibia mid point =.077 mm
    2. Hairs on outer side tibia about 0.12 mm (or well over 0.6x width of hind tibia)

      The measurements above rule out Cinara piceae, which has much shorter hairs - usually less than 0.06 mm (much less than 0.6x width of hind tibia)

    3. Siphuncular cones are darker than rest of cuticle
    4. The hind tibiae are mainly pale
    5. The second hind tarsal segment (HT2) length is 0.28mm
    6. The hind tibia length is 1.83 mm
    7. The length of the 4th and 5th rostral segments (RIV+V) is 0.308mm

    This combination of measurements (see Blackman and Eastop's key) indicates that the species is Cinara hottesi.

    We then applied a much simpler key (given by Bradley) which is restricted to species known to be in Canada on Picea:

    1. Colour light-green. Second tarsal segment exceptionally long and curved .......C. fornacula (Hottes).
      Colour dark. Second tarsal segment not unusually long ........................ 2
    2. Body colour dull bluish-black; legs uniformly orange or yellow ................C. hottesi (Gillette and Palmer).
      Body colour brown; legs dusky...

    To answer your other question "Does age effect colour?" young aphid nymphs can be lighter than the adults. Newly-moulted aphids are light-colored but soon darken and don't change colour thereafter. However your sample also contained quite a few mummies (parasitized aphids) which, as is usual, are rounder and darker than their fellows.

09/02/2014

Thank you. Now I have a name for another amazing bug. The web site I have the images on only has the following Cinara species identified; (fornacula, laricifex, pergandei, pilicornis, pinea, strobi) They will be able to add another page to their records.

The last time I looked at Aphids was to blast the trees with cold water trying to wash everything off. Today, after receiving your email I had another look. One small group remains a few centimeters from the scar on the bark I made, removing the samples you looked at.

Image(s) copyright Stephen McKechnie, all rights reserved.

     

Bob, Influentialpoints: 09/01/2014

  • We have just been taking a look at your pictures of the small 'remaining' group of aphids.

    It looks as if you now have a mixed-species colony of Cinara hottesi and, what we rather suspect may be Cinara pruinosa  - albeit we cannot be sure from photographs, since it's appearance is rather variable, partly because it tends not to have much wax when ant-attended.