﻿REPORT 
  OF 
  TSETSE-FLY 
  INVESTIGATION 
  IN 
  NIGERIA. 
  

  

  385 
  

  

  (e) 
  Evidence 
  of 
  Choice 
  of 
  Diet 
  in 
  G. 
  tachinoides. 
  

  

  As 
  with 
  morsitans, 
  observations 
  on 
  the 
  feeding 
  habits 
  of 
  tachinoides 
  in 
  nature 
  

   are 
  difficult 
  on 
  account 
  of 
  the 
  shyness 
  of 
  the 
  wild 
  animals 
  and 
  the 
  great 
  counter- 
  

   attraction 
  which 
  the 
  observer 
  makes. 
  Their 
  main 
  haunts 
  are 
  too 
  dense 
  for 
  European 
  

   methods 
  of 
  hunting, 
  so 
  that 
  large 
  mammals 
  are 
  rarely 
  shot 
  in 
  the 
  presence 
  of 
  the 
  

   fly. 
  We 
  have 
  found 
  only 
  one 
  definite 
  instance 
  of 
  tachinoides 
  feeding 
  on 
  a 
  game 
  

   animal, 
  and 
  this 
  case 
  was 
  a 
  waterbuck 
  which 
  was 
  wounded 
  in 
  open 
  country 
  and, 
  

   going 
  into 
  close 
  forest, 
  entered 
  a 
  pool, 
  where 
  it 
  was 
  killed. 
  G. 
  tachinoides 
  had 
  

   assailed 
  it 
  in 
  numbers, 
  14 
  being 
  caught 
  in 
  three 
  sweeps 
  of 
  the 
  net, 
  7 
  o* 
  and 
  7 
  °., 
  the 
  

   proportion 
  showing 
  that 
  the 
  flies 
  did 
  not 
  form 
  a 
  following 
  swarm 
  but 
  a 
  feeding 
  group. 
  

   They 
  have 
  often 
  been 
  seen 
  feeding 
  upon 
  goats 
  and 
  dogs. 
  

  

  Laboratory 
  experiments 
  showed 
  that 
  they 
  feed 
  very 
  readily 
  on 
  the 
  tortoise, 
  

   when 
  released 
  in 
  a 
  cage 
  with 
  it, 
  drawing 
  blood 
  from 
  the 
  neck 
  and 
  under 
  the 
  carapace 
  

   near 
  the 
  tail, 
  but 
  the 
  very 
  large 
  blood 
  cells 
  of 
  this 
  animal 
  have 
  not 
  been 
  met 
  with 
  

   in 
  the 
  dissected 
  flies. 
  They 
  also 
  fed 
  freely 
  and 
  repeatedly 
  on 
  a 
  chameleon 
  in 
  a 
  cage, 
  

   the 
  animal 
  not 
  molesting 
  them 
  and 
  appearing 
  indifferent 
  to 
  their 
  attacks. 
  In 
  nature 
  

   the 
  fly 
  certainly 
  feeds 
  on 
  some 
  reptile 
  and 
  almost 
  certainly 
  this 
  is 
  mainly 
  Varanus, 
  

   judging 
  by 
  the 
  localities 
  where 
  this 
  type 
  of 
  blood 
  has 
  been 
  most 
  frequently 
  found 
  

   in 
  the 
  flies. 
  A 
  haemogregarine 
  was 
  occasionally 
  seen 
  with 
  the 
  nucleated 
  red 
  cells 
  

   in 
  the 
  flies, 
  and 
  this 
  is 
  a 
  characteristic 
  blood 
  parasite 
  of 
  Varanus 
  and 
  crocodiles, 
  but 
  

   not 
  of 
  birds. 
  

  

  In 
  a 
  total 
  of 
  1 
  ,500 
  flies 
  examined 
  232 
  contained 
  recognisable 
  blood, 
  non-mammalian 
  

   in 
  37 
  cases 
  (16 
  per 
  cent, 
  of 
  the 
  total). 
  The 
  occurrence 
  of 
  non-mammalian 
  blood 
  was 
  

   thus 
  four 
  times 
  as 
  frequent 
  in 
  tachinoides 
  as 
  in 
  morsitans 
  (4-1 
  per 
  cent.), 
  but 
  less 
  

   frequent 
  than 
  in 
  palpalis 
  (22 
  per 
  cent.) 
  for 
  the 
  whole 
  range 
  of 
  examinations. 
  When 
  

   the 
  localities 
  from 
  which 
  the 
  flies 
  were 
  dissected 
  are 
  divided 
  into 
  two 
  classes 
  according 
  

  

  TABLE 
  III. 
  

  

  Shoiving 
  the 
  Proportion 
  of 
  Non-mammalian 
  to 
  Mammalian 
  Blood 
  in 
  the 
  three 
  prevalent 
  Species 
  of 
  

   Tsetse-flies 
  in 
  the 
  presence 
  or 
  virtual 
  absence 
  of 
  Game. 
  

  

  

  (A). 
  Game 
  virtually 
  absent. 
  

  

  

  Species. 
  

  

  Number 
  

   examined. 
  

  

  Number 
  

  

  containing 
  

  

  recognisable 
  

  

  blood. 
  

  

  Number 
  

  

  containing 
  

  

  nucleated 
  

  

  blood. 
  

  

  Percentage 
  

  

  of 
  

  

  nucleated 
  

  

  blood. 
  

  

  G. 
  palpalis 
  

   G. 
  tachinoides 
  

   G. 
  morsitans 
  

  

  370 
  

  

  407 
  

   Not 
  encountered 
  

  

  70 
  

   83 
  

  

  16 
  

   22 
  

  

  22-9 
  

   26-5 
  

  

  

  

  (B) 
  

  

  . 
  Game 
  present. 
  

  

  

  

  Species. 
  

  

  Number 
  

   examined. 
  

  

  Number 
  

  

  containing 
  

  

  recognisable 
  

  

  blood. 
  

  

  Number 
  

  

  containing 
  

  

  nucleated 
  

  

  blood. 
  

  

  Percentage 
  

  

  of 
  

  

  nucleated 
  

  

  blood. 
  

  

  G. 
  

  

  palpalis 
  

  

  182 
  

  

  26 
  

  

  5 
  

  

  19-2 
  

  

  G. 
  

  

  tachinoides 
  

  

  1 
  ,093 
  

  

  149 
  

  

  15 
  

  

  10-1 
  

  

  G. 
  

  

  morsitans 
  

  

  500 
  

  

  97 
  

  

  4 
  

  

  4-1 
  

  

  