DATA & PRESENTATION

Descriptions of the recording technique, sources of mosquitoes, etc. can be found in the Appendices, together with graphs of the recorded activity. Some of the additional data used here is derived from Taylor & Jones (1969).

At this point, it may be useful to stress that the term "peak" is used for any clearly discernible upsurge in activity. This is essential as, in many, if not most, instances, insects are either light-active or dark-active. The consequence of this is that activity is suppressed, or inhibited, in light conditions opposite to those in which most activity takes place. Here, however, it is the small peaks which are regarded as critical in revealing the influence of the underlying oscillators or clocks.

(b) Generation of sine waves simulating oscillators

The sine waves shown in many of the graphs were generated as follows, using the formulae embodied in the spreadsheet software (Lotus 1-2-3 Release 5 for Windows):

1. The starting point, time zero, had a value zero degrees in the first cell (A1, for example). The next cell (downwards in a column, A2) was taken as time plus 30 minutes, with the entry being +A1+180/x. The value of x was the desired t for the particular sine wave, for example 22.5 when t = 22.5h, and 26 when t = 26h.
2. This formula was copied from cell to cell down the spreadsheet column for as many half-hour intervals as the duration of an experiment might require.
3. In the next column, starting with cell B1 in this example, the entry was @SIN(@DEGTORAD(A1)).
4. This, in turn, was copied from cell to cell down the column for as many cells as necessary. The data thus generated in the second column was used whenever a sine wave with t = x was required.
5. The resultant values, however, range from only +1 to -1. Thus, they were multiplied by an appropriate factor to give values commensurate with the level of the activity in the graphs using experimental data.
6. To simulate LD cycles where Lt and Dt are different, the transition from a sine wave at the first speed to the sine wave at the second speed was made by taking the next highest value for an upwards sector of the wave, or the next lowest value for a downward sector, and so-on for successive full cycles.
7. Other details regarding how the sinewaves were plotted or modulated are given at the appropriate point in the text.

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©1998, 2010 - Brian Taylor CBiol FSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. Comments to dr.b.taylor@ntlworld.com

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