﻿56 
  LL. 
  LLOYD 
  — 
  FURTHER 
  NOTES 
  ON 
  THE 
  BIONOMICS 
  OF 
  

  

  Game 
  destruction. 
  

  

  In 
  view 
  of 
  such 
  facts, 
  it 
  is 
  not 
  certain 
  that 
  the 
  diminution 
  of 
  the 
  fly 
  at 
  the 
  time 
  of 
  

   the 
  rinderpest 
  was 
  due 
  to 
  a 
  reduction 
  of 
  its 
  food 
  supply.* 
  No 
  records 
  of 
  the 
  climatic 
  

   conditions 
  at 
  that 
  time 
  are 
  available. 
  It 
  is 
  known 
  that 
  both 
  high 
  and 
  low 
  tempera- 
  

   tures 
  have 
  a 
  considerable 
  influence 
  on 
  the 
  tsetse-fly 
  and 
  from 
  these 
  or 
  some 
  other 
  

   causes 
  its 
  diminution 
  at 
  the 
  time 
  of 
  the 
  rinderpest 
  may 
  have 
  been 
  merely 
  a 
  coincidence. 
  

   The 
  evidence 
  is 
  not 
  sufficiently 
  definite 
  to 
  warrant 
  the 
  extermination 
  of 
  the 
  larger 
  

   mammals. 
  The 
  first 
  effect 
  of 
  such 
  a 
  course 
  would 
  undoubtedly 
  be 
  that 
  man 
  would 
  

   be 
  more 
  subject 
  to 
  the 
  attacks 
  of 
  the 
  fly. 
  

  

  Further 
  evidence 
  of 
  the 
  relation 
  of 
  the 
  fly 
  to 
  the 
  larger 
  mammals 
  could 
  be 
  obtained 
  

   by 
  compelling 
  it, 
  under 
  as 
  natural 
  conditions 
  as 
  possible, 
  to 
  attempt 
  to 
  support 
  

   itself 
  on 
  a 
  diet 
  of 
  the 
  smaller 
  mammals, 
  birds 
  and 
  reptiles. 
  The 
  following 
  experi- 
  

   ment 
  is 
  therefore 
  suggested. 
  A 
  large 
  fly-proof 
  cage, 
  of 
  some 
  such 
  dimensions 
  as 
  

   100 
  yards 
  long 
  by 
  50 
  yards 
  wide 
  and 
  7 
  feet 
  high, 
  would 
  be 
  constructed 
  on 
  a 
  piece 
  of 
  

   country 
  favoured 
  by 
  tsetse-fly 
  and 
  in 
  which 
  breeding 
  places 
  were 
  known 
  to 
  exist. 
  

   Into 
  this 
  cage 
  would 
  be 
  introduced 
  a 
  number 
  of 
  small 
  mammals 
  and 
  birds, 
  the 
  insecti- 
  

   vorous 
  species 
  being 
  excluded. 
  A 
  large 
  number 
  of 
  tsetse 
  would 
  then 
  be 
  set 
  free 
  in 
  

   the 
  cage 
  and 
  daily 
  observations 
  as 
  to 
  their 
  increase 
  or 
  decrease 
  would 
  be 
  made 
  by 
  a 
  

   well-veiled 
  observer. 
  At 
  the 
  end 
  of 
  twelve 
  months 
  it 
  should 
  be 
  known 
  if 
  the 
  fly 
  is 
  

   able 
  to 
  continue 
  its 
  species 
  on 
  such 
  a 
  fauna. 
  In 
  this 
  event, 
  increase 
  should 
  occur, 
  

   since 
  there 
  would 
  be 
  few 
  enemies 
  in 
  the 
  cage. 
  If 
  the 
  numbers 
  of 
  the 
  fly 
  decreased, 
  

   the 
  experiment 
  would 
  be 
  repeated 
  with 
  the 
  introduction 
  of 
  a 
  few 
  young 
  antelopes, 
  

   goats 
  or 
  sheep 
  into 
  the 
  cage 
  and 
  similar 
  observations 
  would 
  be 
  made 
  over 
  the 
  same 
  

   period. 
  If 
  the 
  increase 
  occurred 
  under 
  these 
  new 
  conditions 
  the 
  dependence 
  of 
  the 
  

   fly 
  on 
  the 
  larger 
  mammals 
  would 
  be 
  made 
  clear. 
  The 
  first 
  of 
  these 
  experiments 
  would 
  

   also 
  yield 
  evidence 
  as 
  to 
  whether 
  the 
  smaller 
  mammals 
  could 
  act 
  as 
  the 
  reservoir 
  of 
  

   the 
  pathogenic 
  trypanosomes 
  of 
  man 
  and 
  domestic 
  stock. 
  

   Distribution 
  of 
  Breeding 
  Places. 
  

  

  Searches 
  for 
  the 
  pupae 
  in 
  nature 
  have 
  resulted 
  in 
  the 
  finding 
  of 
  735 
  living 
  pupae 
  and 
  

   1500 
  empty 
  cases 
  in 
  189 
  positions. 
  A 
  summary 
  of 
  these 
  gives 
  the 
  following 
  results 
  : 
  — 
  

   (a) 
  In 
  40 
  instances 
  the 
  pupae 
  were 
  found 
  in 
  hollows 
  in 
  trees, 
  75 
  pupae 
  and 
  350 
  

   cases 
  being 
  taken. 
  The 
  hollows 
  are 
  at 
  varying 
  heights 
  from 
  the 
  ground 
  

   up 
  to 
  six 
  feet 
  and 
  are 
  sometimes 
  filled 
  with 
  very 
  hard 
  clay 
  and 
  sometimes 
  

   with 
  soft 
  soil, 
  dead 
  leaves, 
  the 
  droppings 
  of 
  insects 
  and 
  the 
  stomach- 
  

   castings 
  of 
  birds. 
  When 
  the 
  surface 
  is 
  hard 
  the 
  living 
  pupae 
  are 
  found 
  

   in 
  crevices 
  or 
  quite 
  exposed 
  on 
  the 
  surface. 
  

   (6) 
  In 
  30 
  instances 
  pupae 
  were 
  found 
  below 
  trees 
  or 
  branches 
  which 
  slope 
  at 
  an 
  

   angle 
  or 
  run 
  parallel 
  to 
  the 
  ground 
  before 
  rising. 
  In 
  such 
  positions 
  129 
  

   pupae 
  and 
  197 
  cases 
  were 
  taken. 
  The 
  ground 
  was 
  usually 
  very 
  hard 
  

   and 
  the 
  pupae 
  were 
  taken 
  on 
  or 
  near 
  the 
  surface 
  or 
  in 
  cracks, 
  

   (c) 
  Beneath 
  fallen 
  dead 
  trees 
  or 
  branches 
  100 
  positions 
  yielded 
  493 
  pupae 
  and 
  

   759 
  cases 
  ; 
  these 
  include 
  the 
  most 
  important 
  breeding 
  places. 
  In 
  such 
  

   places 
  accumulations 
  of 
  dead 
  leaves 
  and 
  twigs 
  usually 
  occur 
  and 
  the 
  

   pupae 
  are 
  found 
  among 
  these. 
  When 
  they 
  are 
  absent, 
  the 
  effort 
  to 
  burrow 
  

   is 
  great 
  and 
  pupae 
  have 
  been 
  taken 
  at 
  a 
  distance 
  of 
  18 
  inches 
  from 
  the 
  

   shelter 
  of 
  the 
  tree. 
  The 
  trunks 
  were 
  often 
  raised 
  one 
  or 
  two 
  feet 
  above 
  

   the 
  ground, 
  so 
  that 
  there 
  was 
  ample 
  room 
  for 
  any 
  insectivorous 
  animal 
  to 
  

   search 
  beneath 
  them. 
  

   * 
  Stevenson 
  Hamilton, 
  Bull. 
  Ent. 
  Kes., 
  ii, 
  pp. 
  113-118. 
  (1911.) 
  

  

  