Time of year determines some, but not all, views of my blog posts

I was going to format this post as a spoof Nature communication, but not being as skilled as our students, who turn out excellently formatted mock papers for their assignments, decided not to. I did, however, go for a typical Nature title 🙂

The other day when I was looking at my blog stats I clicked on the view post stats button next to my most read post of the day, Not all aphids are vegans*, and was amused enough by the strong seasonal dynamics shown to post it on Twitter.

Not all aphids are vegans – strong seasonal dynamics

As you can see, the peaks and troughs of views strongly follow the times of year that aphids are present and absent.

As regular readers of my blog will know, I am a bit of an aphidophile. It is kind of hard to miss if I’m honest, but then aphids are fantastic and awesome, so you will get no apologies from me for loving them and writing, or talking about them whenever I get the chance to do so.

That said, not all my posts are about aphids, insects yes, but I do write about other things too, including entomological equipment, classic papers and teaching matters, and sometimes about my holidays 🙂

Given the strong correlation between aphid life cycle timing and visits to the post about biting aphids, I wondered how my other aphid posts stacked up in terms of seasonal viewing.

Aphid life cycles – bizarre, complex or what?

Somewhat surprisingly, well to me at least, the post about aphid life cycles did not show very strong seasonal dynamics, although April, when aphids start to become active, did, at the beginning of the post’s life, show a bit of a peak of interest, but has since broken down completely.  Another season aspect of aphid biology is wing formation. This is usually associated with late spring and early summer (Dixon, 1973, 1976), and in this case, the viewing history fitted appropriately.

Not all aphids have wings – seasonally appropriate

 

What about the other end of the year, autumn and winter?  As expected, my post about aphid overwintering showed the reverse pattern to the other aphid posts, people wanted to read about aphid overwintering as winter appraoched.

A Winter’s Tale – aphid overwintering

Aphid posts, as predicted, show a correlation (OK, not tested) with the time of year associated with the appropriate part of the life cycle.  We would therefore expect that posts that are more general would show no marked seasonality in their popularity. To test this I looked at first, my posts that deal with entomological equipment, pan traps, clip cages and the poster and then at two posts that fit into the teaching category.  Staring with the Pan trap, a very basic and commonly used piece of field equipment, despite a slight expectation on my part that there might be a spring peak (after all, that is when insects start flying) there was no pattern that I could see.

The pan trap – disappointingly no pattern

 

Nest I looked at the Pooter, an essential bit of general entomological kit (Leather, 2015) used by entomologists of all types. Given that this is used in both the laboratory and the field, I didn’t really expect to see any pattern jumping out at me.  I wasn’t disappointed although if you look very quickly, and not too closely, it is just about possible top convince yourself that there is an increase in views during the summer, which would fit with the general increase in insects caught in nets.

The Pooter – perhaps a slight tendency for views to increase in mid-summer

 

Next, back to aphids, this time a piece of kit that is almost, but not entirely, confined to aphidologists (Macgillivray & Anderson, 1957).  My expectation here, was that given that clip cages are almost always used in laboratories or glasshouses, that there would be absolutely no pattern in the viewing figures. Sure enough, that was the outcome.

The clip cage – no discernible patterns

Finally, the two teaching posts, first my tribute to Southwood’s classic species-area paper (Southwood, 1961).  I know that this post is used for undergraduate teaching at one university, so given the regularity of university timetabling, might have a chance of  showing a pattern;  It didn’t.

Southwood (1961) – the number of insect species associated with various trees – no pattern

Finally, a post that has attracted a modicum of attention over the years, all about what to expect in a PhD viva.  My hypothesis for this, given that most PhD projects start at the beginning of the academic year and run for four or five years before submission, was that if there was going to be an annual peak in views that it would be between October and January.  To save you the troubkle of squinting at the graph, there was no pattern.

Are PhD examiners really ogres? – no consistent peak

In conclusion, aphid posts tend to show viewing patterns consistent with the time of year and life cycle stage, other, more general posts show absolutely no pattern.

 

References

Dixon, A.F.G. (1973) Biology of Aphids. Edward Arnold, London.

Dixon, A.F.G. (1976) Reproductive strategies of the alate morphs of the bird cherry-oat aphid Rhopalosiphum padi. Journal of Animal Ecology, 45, 817-830.

Leather, S.R. (2015) An entomological classic – the Pooter or insect aspirator. British Journal of Entomology & Natural History, 28, 52-54.

MacGillivray, M.E. & Anderson, G.B. (1957) Three useful insect cages. Canadian Entomologist, 89, 43-46.

Southwood, T.R.E. (1961) The number of species of insect associated with various trees. Journal of Animal Ecology, 30, 1-8.

 

*which I have purposely not linked to so as to not influence the count!

 

 

 

Entomological classics – The clip cage

Mention clip cage to an aphidologist and the chances are that they will smile and begin reminiscing about the days when they had to sit down and spend hours refurbishing and making new ones; if they were lucky enough to be in a big research group as I was, they will have had the fun of the communal clip cage renovation day, otherwise they will have laboured doggedly away on their own.  Mention clip cage to an entomologist and they may have heard of them, but probably not used them; to a non-entomologist you will be talking gibberish.  In fact, this week at the beginning of a lecture to the MSc Entomology course here at Harper Adams, I held a clip cage in the air and asked those who knew what it was to put their hands in the air, less than a third were willing to hazard a guess.  For those of you who don’t know the answer, clip cages were invented, or at least revealed in the scientific literature by two Canadian entomologists MacGillivray & Anderson in 1957.  Their purpose, to keep aphids confined individually to leaves of a plant in a simple and effective way.

Before this aphidologists generally used to confine them in large cages covering whole plants, (Davidson, 1925; Kennedy & Booth, 1950).  This allowed the aphids to select their own feeding sites but which of course made knowing what an individual aphid was doing in terms of longevity and fecundity quite difficult.  Kennedy & Booth (1950) were very much aware of this and attempted to solve the problem by using this using this rather over-engineered reproduction cage

This cage, although doing the job was difficult to make and also required a somewhat complicated method of attachment to the plant so as not to pull the leaves off, hence the birth of the

MacGillivray  and Anderson clip cage.  In 1958 another Canadian entomologist Noble described a variant on the MacGillivray & Anderson version where instead of a muslin lid, a cork was used , the theory being that you didn’t need to open the clip to check what the aphid was doing and risk it falling off the leaf, something aphids seem to delight in doing , especially when you are six

 

 days into obtaining seven-day fecundity readings!  Incidentally, this version of the clip cage has resulted in one of my favourite bug-bears, as many people tend to cite Noble (1958) when referring to clip cages, that is if they actually remember to cite anyone at all, and of course they are using the MacGillivray & Anderson version.

Since then the humble clip cage has become the standard way for aphidologists to keep aphids on single leaves of their hosts plants.  They have also been used to confine young Lepidopteran larvae to leaves (Moore et al, 2003) but due to the frass production of lepidopteran larvae are better suited to aphids whose honeydew causes less of a problem for cage cleanliness.  They are very versatile and can be made in different sizes to suit the host plant.   All you need are hair clips,  Perspex tubing and the wherewithal to cut it to the right size, some foam or sponge, fine muslin or  similar textile and a waterproof adhesive.

     

Clip cages are not perfect. There are some drawbacks;  for example, if you don’t move them slightly every day the leaves can develop chlorosis which of course will change the performance of the  aphids  and there is some evidence that the leaf can suffer some physical damage (Moore et al,  2003) and that even if you do move the cages the aphids can behave slightly differently than those in  whole plant cages (Awmack & Leather (2007), but as long you are aware of the possible drawbacks  clip cages remain an indispensable tool for those wishing to study single aphids on whole plants.

And of course, there is the immense satisfaction and sense of achievement of being able to make your own equipment relatively simply and inexpensively.  That said, I certainly received some strange looks when I was working in  Finland and found that there were no clip cages in the lab and had to attempt to buy hair clips in  down-town Helsinki.

Awmack, C. S. & Leather, S. R. (2007).Growth and development. In Aphids as Crop Pests, 135-151 (Eds H. F. Van Emden and R. Harrington). Wallingford: CABI.

Davidson, J. (1925) Biological studies of Aphis ruimicis Linn. factors affecting the infestation of Vicia faba with Aphis rumicis.  Annals of Applied Biology, 12, 472-507

Evans, A.C. (1938) Physiological relationships between insects and their host plants I. The effect of the chemical composition of the plant on reproduction and production of winged forms in Brevicoryne brassicae L. (Aphididae).  Annals of Applied Biology, 25, 558-572

Kennedy, J.S. & Booth, C.O. (1950) Methods for mass rearing and investigating the host relations of Aphis fabae Scop.  Annals of Applied Biology, 37, 451-470

MacGillivray, M. E. &Anderson, G. B. (1957). Three useful insect cages. Canadian Entomologist 89: 43-46.

Noble, M. D. (1958). A simplified clip cage for aphid investigations. Canadian Entomologist 90, 60.

Moore, J.P., a, J.E., Paul, N.D. & Whittaker, J.B. ( 2003)  The use of clip cages to restrain insects    reduces leaf expansion systemically in Rumex obtusifolius Ecological Entomology, 28, 239-242